What is the physical aspect of velocity and thermal slips towards the fluid flow problem especially on skin friction coefficient and heat transfer?

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Taimoor Ali

Velocity Slip:Definition: Velocity slip refers to the difference in velocity between the fluid and the solid surface at the fluid-solid interface. Effect on Skin Friction Coefficient: In microscale and nanoscale flows, where molecular interactions become more pronounced, velocity slip can lead to deviations from the no-slip boundary condition. The skin friction coefficient, which quantifies the frictional drag between the fluid and the solid surface, may be influenced by velocity slip. Slip flow models are often used to account for this slip condition in the analysis of fluid dynamics in micro/nanoscale systems.

Thermal Slip:Definition: Thermal slip, similar to velocity slip, involves a difference in temperature between the fluid and the solid surface at the fluid-solid interface. Effect on Heat Transfer: In microscale and nanoscale flows, thermal slip can impact heat transfer between the fluid and the solid surface. The thermal slip condition leads to a deviation from the conventional no-temperature-jump boundary condition. This can affect the temperature distribution near the solid surface and influence the overall heat transfer characteristics of the system

Ersin Sayar

The velocity slip affects the skin friction coefficient and heat transfer because velocity and temperature distributions are altered because of the slip.

Kristaq Hazizi

The physical aspects of velocity and thermal slips in fluid flow problems have important implications for the skin friction coefficient and heat transfer. Slip boundary conditions refer to the relative motion between the fluid and the solid surface. Here are some key considerations for velocity and thermal slips:

Velocity Slip:In classical fluid mechanics, the no-slip boundary condition is often assumed, meaning that the fluid velocity at the solid boundary is zero. However, in certain situations, slip conditions may be more appropriate. Velocity slip occurs when there is a relative motion between the fluid and the solid surface, leading to a nonzero velocity at the boundary. The slip length is a parameter that characterizes the extent of slip. A larger slip length implies a more significant slip effect.

Thermal Slip:Thermal slip refers to the relative motion between the fluid and the solid surface with respect to temperature. Similar to velocity slip, the no-slip condition is often assumed for temperature at the solid boundary in classical heat transfer problems. However, in certain situations, thermal slip conditions may be more accurate. Thermal slip length is a parameter that characterizes the extent of thermal slip. It is related to how the temperature at the solid-fluid interface deviates from the no-slip condition.

Skin Friction Coefficient:The skin friction coefficient is a measure of the drag force exerted by the fluid on the solid surface. It is influenced by the velocity profile near the boundary. Velocity slip can affect the shear stress distribution at the fluid-solid interface, consequently impacting the skin friction coefficient. A larger slip length generally results in reduced skin friction.

Heat Transfer:Thermal slip influences the temperature distribution near the solid-fluid interface, affecting heat transfer. The heat transfer coefficient at the boundary is influenced by the thermal slip length. A larger thermal slip length can lead to changes in the heat transfer rate.

In summary, considering velocity and thermal slips in fluid flow problems introduces deviations from the traditional no-slip conditions, impacting both the skin friction coefficient and heat transfer characteristics. These effects are particularly relevant in situations where the no-slip assumption may not accurately represent the physical behavior at the fluid-solid interface, such as in microfluidics or nanofluidics.