#viscosity — Public Fediverse posts

These Oil Glup charts are easy to follow. We’ve added notes, so nothing’s missed. Check the links for a proper chat. PAGE 4
#images #oilclub #motoroil #viscosity
https://oil-glup.ru/threads/kartinki-og.483/page-4

Plucking Droplets

A sudden breeze can pluck droplets hanging from a stem. Here, researchers recreate that phenomenon in the laboratory. With a close-up view and high-speed images, we can enjoy every detail of the detachment and break-up. As the wire pulls away, it drags a liquid sheet off the droplet. The thicker rims on either side of the sheet eventually collide, creating a jet that stretches, deforms, and, at last, breaks. (Video and image credit: D. Maity et al.)

Plucking Droplets

A sudden breeze can pluck droplets hanging from a stem. Here, researchers recreate that phenomenon in the laboratory. With a close-up view and high-speed images, we can enjoy every detail of the detachment and break-up. As the wire pulls away, it drags a liquid sheet off the droplet. The thicker rims on either side of the sheet eventually collide, creating a jet that stretches, deforms, and, at last, breaks. (Video and image credit: D. Maity et al.)

Plucking Droplets

A sudden breeze can pluck droplets hanging from a stem. Here, researchers recreate that phenomenon in the laboratory. With a close-up view and high-speed images, we can enjoy every detail of the detachment and break-up. As the wire pulls away, it drags a liquid sheet off the droplet. The thicker rims on either side of the sheet eventually collide, creating a jet that stretches, deforms, and, at last, breaks. (Video and image credit: D. Maity et al.)

Plucking Droplets

A sudden breeze can pluck droplets hanging from a stem. Here, researchers recreate that phenomenon in the laboratory. With a close-up view and high-speed images, we can enjoy every detail of the detachment and break-up. As the wire pulls away, it drags a liquid sheet off the droplet. The thicker rims on either side of the sheet eventually collide, creating a jet that stretches, deforms, and, at last, breaks. (Video and image credit: D. Maity et al.)

Plucking Droplets

A sudden breeze can pluck droplets hanging from a stem. Here, researchers recreate that phenomenon in the laboratory. With a close-up view and high-speed images, we can enjoy every detail of the detachment and break-up. As the wire pulls away, it drags a liquid sheet off the droplet. The thicker rims on either side of the sheet eventually collide, creating a jet that stretches, deforms, and, at last, breaks. (Video and image credit: D. Maity et al.)

Using Navier-Stokes equations and simple experiments, Brown University physicists explored thin liquid films in the kitchen. Milk drains in ~30s, olive oil in 9+ min. Thin film physics everywhere!

🔗 https://phys.org/news/2026-03-liquid-kitchen-physicists.html

#FluidMechanics #ThinFilms #EverydayPhysics #Viscosity #KitchenScience

SAE 20, 30, 40… think you know these numbers? Think again. Behind the labels lies steam-era labs, stopwatches, and a viscosity index myth. Time to see how engine physics crushes marketing tales. #MotorOil #Tribology #SAE #Viscosity #Engine #OilMyths

https://www.youtube.com/watch?v=LhpcI0xHrug

- Capillarity and viscosity: how liquids move -

Understand the relationship between capillarity and viscosity and their role in droplet dynamics with this video from the "Dynamics of fluid interfaces" MOOC by ESPCI Paris - PSL.

🎥 https://www.youtube.com/watch?v=Mq1EUe3cOCY&list=PLcbz7zf4dTyk9BqlBPLpgI48i9TiorpEi&index=13

#Capillarity #Viscosity #FluidPhysics #FluidDynamics

The world is a viscous place.

#viscous #viscosity

The world is a viscous place.

#viscous #viscosity

The world is a viscous place.

#viscous #viscosity

The world is a viscous place.

#viscous #viscosity

- Capillary number: balancing viscosity and surface tension -

The capillary number quantifies how viscosity and surface tension interact in droplets. Explore this key concept in the ESPCI Paris - PSL MOOC video.

🎥 https://www.youtube.com/watch?v=bbEOcd977ec&list=PLcbz7zf4dTyk9BqlBPLpgI48i9TiorpEi&index=12

#CapillaryNumber #Viscosity #SurfaceTension #FluidPhysics #LeidenfrostEffect

Competing Time Scales

Fluid dynamics often comes down to a competition between the different forces acting in a flow. Inertia, surface tension, viscosity, gravity, rotation — flows can be affected by all of these and more. In this video, researchers describe the three dominant forces in a rotating fluid like a planet’s atmosphere: viscosity, the fluid’s resistance to flowing; inertia, the fluid’s resistance to accelerating; and rotation, the overall spin of a fluid.

As shown in the video, which of these three forces dominates will change depending on the speed at which the force acts. We quantify this concept using time scales; the force with the smallest time scale can act fastest and will, therefore, win the tug-of-war. (Video and image credit: UCLA SpinLab)

#DIYFluids #flowVisualization #fluidDynamics #inertia #mathematics #physics #rotatingFlow #science #viscosity

Competing Time Scales

Fluid dynamics often comes down to a competition between the different forces acting in a flow. Inertia, surface tension, viscosity, gravity, rotation — flows can be affected by all of these and more. In this video, researchers describe the three dominant forces in a rotating fluid like a planet’s atmosphere: viscosity, the fluid’s resistance to flowing; inertia, the fluid’s resistance to accelerating; and rotation, the overall spin of a fluid.

As shown in the video, which of these three forces dominates will change depending on the speed at which the force acts. We quantify this concept using time scales; the force with the smallest time scale can act fastest and will, therefore, win the tug-of-war. (Video and image credit: UCLA SpinLab)

#DIYFluids #flowVisualization #fluidDynamics #inertia #mathematics #physics #rotatingFlow #science #viscosity

Competing Time Scales

Fluid dynamics often comes down to a competition between the different forces acting in a flow. Inertia, surface tension, viscosity, gravity, rotation — flows can be affected by all of these and more. In this video, researchers describe the three dominant forces in a rotating fluid like a planet’s atmosphere: viscosity, the fluid’s resistance to flowing; inertia, the fluid’s resistance to accelerating; and rotation, the overall spin of a fluid.

As shown in the video, which of these three forces dominates will change depending on the speed at which the force acts. We quantify this concept using time scales; the force with the smallest time scale can act fastest and will, therefore, win the tug-of-war. (Video and image credit: UCLA SpinLab)

#DIYFluids #flowVisualization #fluidDynamics #inertia #mathematics #physics #rotatingFlow #science #viscosity

Competing Time Scales

Fluid dynamics often comes down to a competition between the different forces acting in a flow. Inertia, surface tension, viscosity, gravity, rotation — flows can be affected by all of these and more. In this video, researchers describe the three dominant forces in a rotating fluid like a planet’s atmosphere: viscosity, the fluid’s resistance to flowing; inertia, the fluid’s resistance to accelerating; and rotation, the overall spin of a fluid.

As shown in the video, which of these three forces dominates will change depending on the speed at which the force acts. We quantify this concept using time scales; the force with the smallest time scale can act fastest and will, therefore, win the tug-of-war. (Video and image credit: UCLA SpinLab)

#DIYFluids #flowVisualization #fluidDynamics #inertia #mathematics #physics #rotatingFlow #science #viscosity

Competing Time Scales

Fluid dynamics often comes down to a competition between the different forces acting in a flow. Inertia, surface tension, viscosity, gravity, rotation — flows can be affected by all of these and more. In this video, researchers describe the three dominant forces in a rotating fluid like a planet’s atmosphere: viscosity, the fluid’s resistance to flowing; inertia, the fluid’s resistance to accelerating; and rotation, the overall spin of a fluid.

As shown in the video, which of these three forces dominates will change depending on the speed at which the force acts. We quantify this concept using time scales; the force with the smallest time scale can act fastest and will, therefore, win the tug-of-war. (Video and image credit: UCLA SpinLab)

#DIYFluids #flowVisualization #fluidDynamics #inertia #mathematics #physics #rotatingFlow #science #viscosity

Classical Fluid Analogies for Schrödinger-Newton Systems

I thought I’d mention here a paper now on arXiv that I co-wrote with my PhD student Aoibhinn Gallagher. Here is the abstract:

The Schrödinger-Poisson formalism has found a number of applications in cosmology, particularly in describing the growth by gravitational instability of large-scale structure in a universe dominated by ultra-light scalar particles. Here we investigate the extent to which the behaviour of this and the more general case of a Schrödinger-Newton system, can be described in terms of classical fluid concepts such as viscosity and pressure. We also explore whether such systems can be described by a pseudo-Reynolds number as for classical viscous fluids. The conclusion we reach is that this is indeed possible, but with important restrictions to ensure physical consistency.

arXiv:2507.08583

It is based on work that his in her now-completed PhD thesis, along with another paper mentioned here. I have been interested for many years in the Schrödinger-Newton system (or, more specifically, the Schrödinger-Poisson system in the case where self-gravitational forces are involved). In its simplest form this involves a wave-mechanical representation, in the form of an effective Schrödinger equation, of potential flow described classically by an Euler equation. More recently we got interested in the extent to which such an approach could be used to model viscous fluids represented by a Navier-Stokes equation rather than an Euler equation. That was largely because the effective Planck constant that arises in this representation has the same dimensions as kinematic viscosity (but there’s more to it than that).

In the paper we explored a limited aspect of this, by looking at situations where there is no vorticity (so still a potential flow) but there is viscosity. There aren’t many examples of fluid flow in which there is viscosity but no vorticity, and most of those that do exist are about one-dimensional flow along channels or pipes with boundary conditions that don’t really apply to astrophysics, but one example we did look at in detail was the dissipiation of longitudinal waves in such a fluid.

One upshot of this work is that one can indeed describe some aspects of quantum-mechnical fluids such as ultra-light scalar matter in terms of classical fluid properties, such as viscosity, but you have to be careful. For more information, read the paper!

#AoibhinnGallagher #NavierStokesEquations #SchrödingerEquation #SchrödingerPoissonSystem #viscosity

Classical Fluid Analogies for Schrödinger-Newton Systems

I thought I’d mention here a paper now on arXiv that I co-wrote with my PhD student Aoibhinn Gallagher. Here is the abstract:

The Schrödinger-Poisson formalism has found a number of applications in cosmology, particularly in describing the growth by gravitational instability of large-scale structure in a universe dominated by ultra-light scalar particles. Here we investigate the extent to which the behaviour of this and the more general case of a Schrödinger-Newton system, can be described in terms of classical fluid concepts such as viscosity and pressure. We also explore whether such systems can be described by a pseudo-Reynolds number as for classical viscous fluids. The conclusion we reach is that this is indeed possible, but with important restrictions to ensure physical consistency.

arXiv:2507.08583

It is based on work that his in her now-completed PhD thesis, along with another paper mentioned here. I have been interested for many years in the Schrödinger-Newton system (or, more specifically, the Schrödinger-Poisson system in the case where self-gravitational forces are involved). In its simplest form this involves a wave-mechanical representation, in the form of an effective Schrödinger equation, of potential flow described classically by an Euler equation. More recently we got interested in the extent to which such an approach could be used to model viscous fluids represented by a Navier-Stokes equation rather than an Euler equation. That was largely because the effective Planck constant that arises in this representation has the same dimensions as kinematic viscosity (but there’s more to it than that).

In the paper we explored a limited aspect of this, by looking at situations where there is no vorticity (so still a potential flow) but there is viscosity. There aren’t many examples of fluid flow in which there is viscosity but no vorticity, and most of those that do exist are about one-dimensional flow along channels or pipes with boundary conditions that don’t really apply to astrophysics, but one example we did look at in detail was the dissipiation of longitudinal waves in such a fluid.

One upshot of this work is that one can indeed describe some aspects of quantum-mechnical fluids such as ultra-light scalar matter in terms of classical fluid properties, such as viscosity, but you have to be careful. For more information, read the paper!

#AoibhinnGallagher #NavierStokesEquations #SchrödingerEquation #SchrödingerPoissonSystem #viscosity

Venusian Gravity Currents

Radar measurements of Venus‘s surface reveal the remains of many volcanic eruptions. One type of feature, known as a pancake dome, has a very flat top and steep sides; one dome, Narina Tholus, is over 140 kilometers wide. Since their discovery, scientists have been puzzling out how such domes could form. A recent study suggests that the Venusian surface’s elasticity plays a role.

According to current models, the pancake domes are gravity currents (like a cold draft under your door, an avalanche, or the Boston Molasses Flood), albeit ones so viscous that they may require hundreds of thousands of Earth-years to settle. Researchers found that their simulated pancake domes best matched measurements from Venus when the lava was about 2.5 times denser than water and flowed over a flexible crust.

We might have more data to support (or refute) the study’s conclusions soon, but only if NASA’s VERITAS mission to Venus is not cancelled. (Image credit: NASA; research credit: M. Borelli et al.; via Gizmodo)

#fluidDynamics #gravityCurrents #physics #planetaryScience #science #venus #viscosity #viscousFlow #volcano

Venusian Gravity Currents

Radar measurements of Venus‘s surface reveal the remains of many volcanic eruptions. One type of feature, known as a pancake dome, has a very flat top and steep sides; one dome, Narina Tholus, is over 140 kilometers wide. Since their discovery, scientists have been puzzling out how such domes could form. A recent study suggests that the Venusian surface’s elasticity plays a role.

According to current models, the pancake domes are gravity currents (like a cold draft under your door, an avalanche, or the Boston Molasses Flood), albeit ones so viscous that they may require hundreds of thousands of Earth-years to settle. Researchers found that their simulated pancake domes best matched measurements from Venus when the lava was about 2.5 times denser than water and flowed over a flexible crust.

We might have more data to support (or refute) the study’s conclusions soon, but only if NASA’s VERITAS mission to Venus is not cancelled. (Image credit: NASA; research credit: M. Borelli et al.; via Gizmodo)

#fluidDynamics #gravityCurrents #physics #planetaryScience #science #venus #viscosity #viscousFlow #volcano

Venusian Gravity Currents

Radar measurements of Venus‘s surface reveal the remains of many volcanic eruptions. One type of feature, known as a pancake dome, has a very flat top and steep sides; one dome, Narina Tholus, is over 140 kilometers wide. Since their discovery, scientists have been puzzling out how such domes could form. A recent study suggests that the Venusian surface’s elasticity plays a role.

According to current models, the pancake domes are gravity currents (like a cold draft under your door, an avalanche, or the Boston Molasses Flood), albeit ones so viscous that they may require hundreds of thousands of Earth-years to settle. Researchers found that their simulated pancake domes best matched measurements from Venus when the lava was about 2.5 times denser than water and flowed over a flexible crust.

We might have more data to support (or refute) the study’s conclusions soon, but only if NASA’s VERITAS mission to Venus is not cancelled. (Image credit: NASA; research credit: M. Borelli et al.; via Gizmodo)

#fluidDynamics #gravityCurrents #physics #planetaryScience #science #venus #viscosity #viscousFlow #volcano

Venusian Gravity Currents

Radar measurements of Venus‘s surface reveal the remains of many volcanic eruptions. One type of feature, known as a pancake dome, has a very flat top and steep sides; one dome, Narina Tholus, is over 140 kilometers wide. Since their discovery, scientists have been puzzling out how such domes could form. A recent study suggests that the Venusian surface’s elasticity plays a role.

According to current models, the pancake domes are gravity currents (like a cold draft under your door, an avalanche, or the Boston Molasses Flood), albeit ones so viscous that they may require hundreds of thousands of Earth-years to settle. Researchers found that their simulated pancake domes best matched measurements from Venus when the lava was about 2.5 times denser than water and flowed over a flexible crust.

We might have more data to support (or refute) the study’s conclusions soon, but only if NASA’s VERITAS mission to Venus is not cancelled. (Image credit: NASA; research credit: M. Borelli et al.; via Gizmodo)

#fluidDynamics #gravityCurrents #physics #planetaryScience #science #venus #viscosity #viscousFlow #volcano

Venusian Gravity Currents

Radar measurements of Venus‘s surface reveal the remains of many volcanic eruptions. One type of feature, known as a pancake dome, has a very flat top and steep sides; one dome, Narina Tholus, is over 140 kilometers wide. Since their discovery, scientists have been puzzling out how such domes could form. A recent study suggests that the Venusian surface’s elasticity plays a role.

According to current models, the pancake domes are gravity currents (like a cold draft under your door, an avalanche, or the Boston Molasses Flood), albeit ones so viscous that they may require hundreds of thousands of Earth-years to settle. Researchers found that their simulated pancake domes best matched measurements from Venus when the lava was about 2.5 times denser than water and flowed over a flexible crust.

We might have more data to support (or refute) the study’s conclusions soon, but only if NASA’s VERITAS mission to Venus is not cancelled. (Image credit: NASA; research credit: M. Borelli et al.; via Gizmodo)

#fluidDynamics #gravityCurrents #physics #planetaryScience #science #venus #viscosity #viscousFlow #volcano

Room-Temperature Zwitterionic Liquids You Can Actually Stir:
Incorporation of a flexible oligoether chain into the spacer between cationic and anionic units reduces viscosity effectively
https://www.chemistryviews.org/room-temperature-zwitterionic-liquids-you-can-actually-stir/

#zwitterionicliquids #viscosity #chemistry #chemistryviews #chemviews

Room-Temperature Zwitterionic Liquids You Can Actually Stir:
Incorporation of a flexible oligoether chain into the spacer between cationic and anionic units reduces viscosity effectively
https://www.chemistryviews.org/room-temperature-zwitterionic-liquids-you-can-actually-stir/

#zwitterionicliquids #viscosity #chemistry #chemistryviews #chemviews

Room-Temperature Zwitterionic Liquids You Can Actually Stir:
Incorporation of a flexible oligoether chain into the spacer between cationic and anionic units reduces viscosity effectively
https://www.chemistryviews.org/room-temperature-zwitterionic-liquids-you-can-actually-stir/

#zwitterionicliquids #viscosity #chemistry #chemistryviews #chemviews

Room-Temperature Zwitterionic Liquids You Can Actually Stir:
Incorporation of a flexible oligoether chain into the spacer between cationic and anionic units reduces viscosity effectively
https://www.chemistryviews.org/room-temperature-zwitterionic-liquids-you-can-actually-stir/

#zwitterionicliquids #viscosity #chemistry #chemistryviews #chemviews

Room-Temperature Zwitterionic Liquids You Can Actually Stir:
Incorporation of a flexible oligoether chain into the spacer between cationic and anionic units reduces viscosity effectively
https://www.chemistryviews.org/room-temperature-zwitterionic-liquids-you-can-actually-stir/

#zwitterionicliquids #viscosity #chemistry #chemistryviews #chemviews

I'll take the opportunity to open a small parenthesis on what #rheology aka “the science of the flow”, is: the term, which can be used both for fluids and (some classes of) deformable solids describes the relationship between stress and strain in a continumm.

To wit, for something to flow (or deform), there must be a force applied. The relation between this force and how much (and how quickly) the continuum deforms is what rheology is about.

Rheology deals with two main classes of behavior: #plasticity and #viscosity.

Plastic behavior refers to (permanent) deformations whose magnitude depends on the applied force: smaller forces result in smaller deformations, larger forces in larger deformations. This is typical of solids.

Viscous behavior refers to deformations whose rate depends on the applied force: in this sense deformations can be “infinite” (the distance between two given points can grow arbitrarily), and as long as the force is applied the deformation will grow. #Viscosity determines how strongly the continuum (typically a fluid) resits to the deformation, and thus how quickly (or slowly) it deforms.

And of course you can have hybrid behaviors (viscoplastic, viscoelastic, viscoplastoelastic).

5/

I'll take the opportunity to open a small parenthesis on what #rheology aka “the science of the flow”, is: the term, which can be used both for fluids and (some classes of) deformable solids describes the relationship between stress and strain in a continumm.

To wit, for something to flow (or deform), there must be a force applied. The relation between this force and how much (and how quickly) the continuum deforms is what rheology is about.

Rheology deals with two main classes of behavior: #plasticity and #viscosity.

Plastic behavior refers to (permanent) deformations whose magnitude depends on the applied force: smaller forces result in smaller deformations, larger forces in larger deformations. This is typical of solids.

Viscous behavior refers to deformations whose rate depends on the applied force: in this sense deformations can be “infinite” (the distance between two given points can grow arbitrarily), and as long as the force is applied the deformation will grow. #Viscosity determines how strongly the continuum (typically a fluid) resits to the deformation, and thus how quickly (or slowly) it deforms.

And of course you can have hybrid behaviors (viscoplastic, viscoelastic, viscoplastoelastic).

5/

I'll take the opportunity to open a small parenthesis on what #rheology aka “the science of the flow”, is: the term, which can be used both for fluids and (some classes of) deformable solids describes the relationship between stress and strain in a continumm.

To wit, for something to flow (or deform), there must be a force applied. The relation between this force and how much (and how quickly) the continuum deforms is what rheology is about.

Rheology deals with two main classes of behavior: #plasticity and #viscosity.

Plastic behavior refers to (permanent) deformations whose magnitude depends on the applied force: smaller forces result in smaller deformations, larger forces in larger deformations. This is typical of solids.

Viscous behavior refers to deformations whose rate depends on the applied force: in this sense deformations can be “infinite” (the distance between two given points can grow arbitrarily), and as long as the force is applied the deformation will grow. #Viscosity determines how strongly the continuum (typically a fluid) resits to the deformation, and thus how quickly (or slowly) it deforms.

And of course you can have hybrid behaviors (viscoplastic, viscoelastic, viscoplastoelastic).

5/

I'll take the opportunity to open a small parenthesis on what #rheology aka “the science of the flow”, is: the term, which can be used both for fluids and (some classes of) deformable solids describes the relationship between stress and strain in a continumm.

To wit, for something to flow (or deform), there must be a force applied. The relation between this force and how much (and how quickly) the continuum deforms is what rheology is about.

Rheology deals with two main classes of behavior: #plasticity and #viscosity.

Plastic behavior refers to (permanent) deformations whose magnitude depends on the applied force: smaller forces result in smaller deformations, larger forces in larger deformations. This is typical of solids.

Viscous behavior refers to deformations whose rate depends on the applied force: in this sense deformations can be “infinite” (the distance between two given points can grow arbitrarily), and as long as the force is applied the deformation will grow. #Viscosity determines how strongly the continuum (typically a fluid) resits to the deformation, and thus how quickly (or slowly) it deforms.

And of course you can have hybrid behaviors (viscoplastic, viscoelastic, viscoplastoelastic).

5/

I'll take the opportunity to open a small parenthesis on what #rheology aka “the science of the flow”, is: the term, which can be used both for fluids and (some classes of) deformable solids describes the relationship between stress and strain in a continumm.

To wit, for something to flow (or deform), there must be a force applied. The relation between this force and how much (and how quickly) the continuum deforms is what rheology is about.

Rheology deals with two main classes of behavior: #plasticity and #viscosity.

Plastic behavior refers to (permanent) deformations whose magnitude depends on the applied force: smaller forces result in smaller deformations, larger forces in larger deformations. This is typical of solids.

Viscous behavior refers to deformations whose rate depends on the applied force: in this sense deformations can be “infinite” (the distance between two given points can grow arbitrarily), and as long as the force is applied the deformation will grow. #Viscosity determines how strongly the continuum (typically a fluid) resits to the deformation, and thus how quickly (or slowly) it deforms.

And of course you can have hybrid behaviors (viscoplastic, viscoelastic, viscoplastoelastic).

5/

A New Mantle Viscosity Shift

The rough picture of Earth’s interior — a crust, mantle, and core — is well-known, but the details of its inner structure are more difficult to pin down. A recent study analyzed seismic wave data with a machine learning algorithm to identify regions of the mantle where waves slowed down. These shifts in seismic wave speed occur in areas where the mantle’s viscosity changes; a higher viscosity makes waves travel slower.

The team found seismic wave speed shifts at depths of 400 and 650 kilometers, corresponding to known viscosity changes. But they found shifts at 1050 and 1500 kilometers, as well — the first time anyone has shown a global viscosity shift at those depths. Their analysis suggests a higher viscosity in this mid-mantle transition zone, which could affect how tectonic plates, which rely on these slow mantle flows, move. (Image credit: NASA; research credit: K. O’Farrell and Y. Wang; via Eos)

#fluidDynamics #geophysics #mantleConvection #physics #planetaryScience #science #viscosity

A New Mantle Viscosity Shift

The rough picture of Earth’s interior — a crust, mantle, and core — is well-known, but the details of its inner structure are more difficult to pin down. A recent study analyzed seismic wave data with a machine learning algorithm to identify regions of the mantle where waves slowed down. These shifts in seismic wave speed occur in areas where the mantle’s viscosity changes; a higher viscosity makes waves travel slower.

The team found seismic wave speed shifts at depths of 400 and 650 kilometers, corresponding to known viscosity changes. But they found shifts at 1050 and 1500 kilometers, as well — the first time anyone has shown a global viscosity shift at those depths. Their analysis suggests a higher viscosity in this mid-mantle transition zone, which could affect how tectonic plates, which rely on these slow mantle flows, move. (Image credit: NASA; research credit: K. O’Farrell and Y. Wang; via Eos)

#fluidDynamics #geophysics #mantleConvection #physics #planetaryScience #science #viscosity

A New Mantle Viscosity Shift

The rough picture of Earth’s interior — a crust, mantle, and core — is well-known, but the details of its inner structure are more difficult to pin down. A recent study analyzed seismic wave data with a machine learning algorithm to identify regions of the mantle where waves slowed down. These shifts in seismic wave speed occur in areas where the mantle’s viscosity changes; a higher viscosity makes waves travel slower.

The team found seismic wave speed shifts at depths of 400 and 650 kilometers, corresponding to known viscosity changes. But they found shifts at 1050 and 1500 kilometers, as well — the first time anyone has shown a global viscosity shift at those depths. Their analysis suggests a higher viscosity in this mid-mantle transition zone, which could affect how tectonic plates, which rely on these slow mantle flows, move. (Image credit: NASA; research credit: K. O’Farrell and Y. Wang; via Eos)

#fluidDynamics #geophysics #mantleConvection #physics #planetaryScience #science #viscosity

A New Mantle Viscosity Shift

The rough picture of Earth’s interior — a crust, mantle, and core — is well-known, but the details of its inner structure are more difficult to pin down. A recent study analyzed seismic wave data with a machine learning algorithm to identify regions of the mantle where waves slowed down. These shifts in seismic wave speed occur in areas where the mantle’s viscosity changes; a higher viscosity makes waves travel slower.

The team found seismic wave speed shifts at depths of 400 and 650 kilometers, corresponding to known viscosity changes. But they found shifts at 1050 and 1500 kilometers, as well — the first time anyone has shown a global viscosity shift at those depths. Their analysis suggests a higher viscosity in this mid-mantle transition zone, which could affect how tectonic plates, which rely on these slow mantle flows, move. (Image credit: NASA; research credit: K. O’Farrell and Y. Wang; via Eos)

#fluidDynamics #geophysics #mantleConvection #physics #planetaryScience #science #viscosity

A New Mantle Viscosity Shift

The rough picture of Earth’s interior — a crust, mantle, and core — is well-known, but the details of its inner structure are more difficult to pin down. A recent study analyzed seismic wave data with a machine learning algorithm to identify regions of the mantle where waves slowed down. These shifts in seismic wave speed occur in areas where the mantle’s viscosity changes; a higher viscosity makes waves travel slower.

The team found seismic wave speed shifts at depths of 400 and 650 kilometers, corresponding to known viscosity changes. But they found shifts at 1050 and 1500 kilometers, as well — the first time anyone has shown a global viscosity shift at those depths. Their analysis suggests a higher viscosity in this mid-mantle transition zone, which could affect how tectonic plates, which rely on these slow mantle flows, move. (Image credit: NASA; research credit: K. O’Farrell and Y. Wang; via Eos)

#fluidDynamics #geophysics #mantleConvection #physics #planetaryScience #science #viscosity

When surface tension varies along an interface, fluids move from regions of low surface tension to higher surface tension, a behavior known as the Marangoni effect. Here, a drop of (dyed) water is placed on glycerol. The two fluids are miscible, but water has much a lower viscosity and density yet a higher surface tension. The drop’s interface quickly becomes unstable; viscous fingers form along the edge as the less viscous water pushes into the more viscous glycerol. Eventually, the surface-tension-driven Marangoni flow breaks those fingers off into lip-like daughter drops. The researchers also show how the interplay between viscosity and surface tension affects the size of fingers that form by varying the water/glycerol concentration. (Image and video credit: A. Hooshanginejad et al.)

https://fyfluiddynamics.com/2024/10/marangoni-blossoms/

#2021gofm #fluidDynamics #instability #marangoniEffect #physics #science #surfaceTension #viscosity #viscousFingering

Thomas Strassner and Stefan Fritsch @tudresden present a new class of tunable aryl alkyl ionic liquids (TAAILs) ➡️ https://www.beilstein-journals.org/bjoc/articles/20/110?M=y

#conductivity #IonicLiquids #viscosity
#DiamondOpenAccess 💎🔓 #BJOC

Thomas Strassner and Stefan Fritsch @tudresden present a new class of tunable aryl alkyl ionic liquids (TAAILs) ➡️ https://www.beilstein-journals.org/bjoc/articles/20/110?M=y

#conductivity #IonicLiquids #viscosity
#DiamondOpenAccess 💎🔓 #BJOC

Thomas Strassner and Stefan Fritsch @tudresden present a new class of tunable aryl alkyl ionic liquids (TAAILs) ➡️ https://www.beilstein-journals.org/bjoc/articles/20/110?M=y

#conductivity #IonicLiquids #viscosity
#DiamondOpenAccess 💎🔓 #BJOC

Thomas Strassner and Stefan Fritsch @tudresden present a new class of tunable aryl alkyl ionic liquids (TAAILs) ➡️ https://www.beilstein-journals.org/bjoc/articles/20/110?M=y

#conductivity #IonicLiquids #viscosity
#DiamondOpenAccess 💎🔓 #BJOC

Thomas Strassner and Stefan Fritsch @tudresden present a new class of tunable aryl alkyl ionic liquids (TAAILs) ➡️ https://www.beilstein-journals.org/bjoc/articles/20/110?M=y

#conductivity #IonicLiquids #viscosity
#DiamondOpenAccess 💎🔓 #BJOC

These days glass screens travel with us everywhere, and they can take some big hits on the way. Manufacturers have made tougher glass, but they continue to look for ways to protect our screens. Recently, a study suggested that non-Newtonian fluids are well-suited to the task.

The team explored the physics of sandwiching a layer of fluid between a glass top layer and an LCD screen bottom layer, mimicking structures found in electronic devices. Through simulation, they searched for the fluid characteristics that would best minimize the forces felt by the solid layers during an impact. They found that shear-thinning fluids — fluids that, like paint or shampoo, get runnier when they’re deformed — provided the best protection. Having the impact energy go into reducing the local viscosity of the fluid stretches the length of time the impact affects the glass, which lowers the bending forces on it and helps avoid breakage. (Image credit: G. Rosenke; research credit: J. Richards et al.; via Physics World)

https://fyfluiddynamics.com/2024/05/saving-screens-with-shear-thinning-fluids/

#engineering #fluidDynamics #nonNewtonianFluids #numericalSimulation #physics #science #shearThinning #solidMechanics #viscosity

These days glass screens travel with us everywhere, and they can take some big hits on the way. Manufacturers have made tougher glass, but they continue to look for ways to protect our screens. Recently, a study suggested that non-Newtonian fluids are well-suited to the task.

The team explored the physics of sandwiching a layer of fluid between a glass top layer and an LCD screen bottom layer, mimicking structures found in electronic devices. Through simulation, they searched for the fluid characteristics that would best minimize the forces felt by the solid layers during an impact. They found that shear-thinning fluids — fluids that, like paint or shampoo, get runnier when they’re deformed — provided the best protection. Having the impact energy go into reducing the local viscosity of the fluid stretches the length of time the impact affects the glass, which lowers the bending forces on it and helps avoid breakage. (Image credit: G. Rosenke; research credit: J. Richards et al.; via Physics World)

https://fyfluiddynamics.com/2024/05/saving-screens-with-shear-thinning-fluids/

#engineering #fluidDynamics #nonNewtonianFluids #numericalSimulation #physics #science #shearThinning #solidMechanics #viscosity

If you sandwich a viscous fluid between two plates and inject a less viscous fluid, you’ll get viscous fingers that spread and split as they grow. This research poster depicts that situation with a slight twist: the viscous fluid (transparent in the image) is shear-thinning. That means its viscosity drops when it’s deformed. In this situation, the fingers formed by the injected (blue) fluid start out the way we’d expect: splitting as they grow (inner portion of the composite image). But then, the tip-splitting stops and the fingers instead elongate into spikes (middle ring). Eventually, as the outer fluid’s viscosity drops further, the fingers round out and spread without splitting (outer arc of the image). (Image credit: E. Dakov et al.; via GoSM)

https://fyfluiddynamics.com/2024/04/evolving-fingers/

#2024gosmp #flowVisualization #fluidDynamics #HeleShawCell #instability #nonNewtonianFluids #physics #SaffmanTaylorInstability #science #shearThinning #surfaceTension #viscosity #viscousFingering