Fluid mechanics question--slip boundary condition for gas?

In summary, a slip boundary condition is a type of boundary condition that describes the behavior of a fluid at the interface between a solid surface and the fluid. It specifies how the fluid velocity and shear stress are related at the surface, and can differ between gases and liquids due to their molecular structures. Factors such as gas viscosity, surface roughness, temperature, and pressure can affect the slip boundary condition for gas. It is important in gas flow calculations as it can significantly impact the accuracy of the results. The slip boundary condition can be experimentally determined through various techniques such as surface force apparatus, atomic force microscopy, and microchannel flow measurements.
  • #1
Yinxiao Li
46
0
In solving the Navier Stokes equation, the typical boundary condition imposed on the tangential velocity at a solid surface is that of no-slip. However, it is known that for gaseous flow there always exists a non-zero velocity near the wall, especially at relatively big Knudsen number.
Is there any good book/paper that I can get such information? In particular, I am interested in the slip velocity of nitrogen gas at Kn=0.07~0.1.
Thanks!
 
Engineering news on Phys.org
  • #2
Google: Knudsen Number non-slip
 

FAQ: Fluid mechanics question--slip boundary condition for gas?

What is a slip boundary condition in fluid mechanics?

A slip boundary condition is a type of boundary condition that describes the behavior of a fluid at the interface between a solid surface and the fluid. It specifies how the fluid velocity and shear stress are related at the surface, and whether the fluid is able to slip or stick to the surface.

How does the slip boundary condition for gas differ from that of liquids?

The slip boundary condition for gas differs from that of liquids due to the different molecular structures and interactions between the two states of matter. Gas molecules have more freedom of movement and are less likely to adhere to a solid surface, resulting in a larger slip length and a weaker slip boundary condition compared to liquids.

What factors affect the slip boundary condition for gas?

The slip boundary condition for gas is affected by several factors, including the gas viscosity, surface roughness, temperature, and pressure. Higher gas viscosity and surface roughness tend to decrease the slip length and strengthen the slip boundary condition, while higher temperature and pressure can increase the slip length and weaken the slip boundary condition.

Why is the slip boundary condition important in gas flow calculations?

The slip boundary condition is important in gas flow calculations because it affects the fluid velocity and shear stress at the surface, which in turn affects the overall flow behavior and can significantly impact the accuracy of the calculations. Ignoring the slip boundary condition can lead to incorrect results and predictions.

How is the slip boundary condition experimentally determined?

The slip boundary condition can be experimentally determined using techniques such as surface force apparatus, atomic force microscopy, and microchannel flow measurements. These methods involve measuring the fluid velocity and shear stress at the surface and comparing them to theoretical predictions based on different slip boundary conditions to determine the most accurate fit.

Similar threads

Fluid solid interaction boundary condition problem
Replies
1
Views
1K
COMSOL two phase flow with slip boundary condition
Replies
1
Views
7K
I Immersed Boundary method and No-Slip condition
Replies
1
Views
1K
Incompressibility in boundary layer (Fluid Dynamics)
Replies
1
Views
2K
I Boundary Conditions For Modelling of a Fluid Using Euler's Equations
Replies
16
Views
2K
No slip condition in an ideal fluid- Perpendicular pressure
Replies
13
Views
3K
I No Slip condition in an Inviscid Fluid
Replies
1
Views
4K
A Why are the Navier-Stokes equations inconsistent in this case?
Replies
18
Views
2K
Scattering dynamics and viscosity
Replies
1
Views
981
Stream function along solid boundary
Replies
1
Views
6K

Hot Threads

Recent Insights

Back
Top