Shear viscosity of liquid mixtures: mass dependence
1Department of Physics, Panjab University, Chandigarh 160014, India.
Summary
This study derives sum rules for fluid mixtures, finding good agreement with simulations for Ar-Kr shear viscosity. Mass differences significantly impact viscosity, deviating from ideal models at higher mass ratios.
Area of Science:
- Fluid dynamics
- Statistical mechanics
- Computational physics
Background:
- Understanding the shear viscosity of multi-component fluid mixtures is crucial for various physical and chemical processes.
- Existing models often simplify the complex interactions and mass differences present in such systems.
Purpose of the Study:
- To derive sum rules for the transverse stress autocorrelation function in two-component fluids.
- To investigate the shear viscosity of Argon-Krypton (Ar-Kr) and isotopic mixtures using these sum rules and Mori's memory function formalism.
- To analyze the mass dependence of shear viscosity and its deviation from empirical models.
Main Methods:
- Derivation of zeroth, second, and fourth sum rules for the transverse stress autocorrelation function.
- Application of Mori's memory function formalism.
- Comparison of theoretical results with computer simulation data for Ar-Kr mixtures.
Main Results:
- Theoretical expressions for sum rules were successfully derived.
- The derived sum rules and formalism showed good agreement with computer simulations for Ar-Kr shear viscosity.
- Significant deviations from ideal linear models were observed due to mass differences between fluid components.
- Empirical models failed to explain shear viscosity at higher mass ratios.
Conclusions:
- The derived sum rules provide a valuable tool for studying fluid mixture properties.
- Mass differences play a critical role in determining shear viscosity, even in mixtures of similar elements.
- Advanced theoretical or computational approaches are needed to accurately model shear viscosity in mixtures with significant mass disparities.
Related Concept Videos
02:57Surface Tension, Capillary Action, and Viscosity
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
01:17Viscosity
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
01:20Stokes' Law
Viscous forces, like friction, are intermolecular forces that resist the relative motion of molecules over each other. When a solid body moves through a liquid, viscous forces drag it in the opposite direction. The force's magnitude depends on the solid's shape and size, as well as its speed and the liquid's coefficient of viscosity, density and temperature.
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
01:27Viscosity
Viscosity is a property of fluids that measures their resistance to flow. It is influenced by factors such as the surface area of contact, the gradient of flow speed, and the fluid's viscosity constant, called the coefficient of viscosity. The coefficient of viscosity, also known as dynamic viscosity, is denoted by the symbol η. It determines the proportionality between the viscous force and the gradient of flow speed.Newton's law of viscosity states that the viscous force on a faster-moving...
01:19Viscosity of Fluid
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
01:18Newtonian Fluid: Problem Solving
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...