Calculating Flow Separation Point

In summary, calculating the point at which flow separation occurs is a difficult problem that has been extensively studied in the field of physical fluid dynamics. Tritton's book "Physical Fluid Dynamics" and Lamb's book "Hydrodynamics" both have discussions on this topic. The critical angle for a diffuser on a car can be determined by using standard airfoil theory, which has been extensively researched for high Reynolds number flow separation.
  • #1
no1schuifan
14
0
Does anyone know of a way to calculate the point at which flow separation occurs?
 
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  • #2
Tritton (Physical Fluid Dynamics) has a qualitative discussion on chapter 12, and Lamb (Hydrodynamics) has a few sections as well.

The problem is extremely difficult, in the linear case separation ocurrs where the normal component of flow vanishes. This leaves open the problem of calculating the flow.
 
  • #3
Thanks for your help. The reason i ask is I'm trying to find the critical angle for a diffuser on a car to produce the most downforce so being able to work out past which angle the flow separates from the diffuser is key. Do you think it is worth looking into more or am i aiming for somethign that's just unreasonable?
 
  • #4
The good news is that standard airfoil theory should be sufficient for your case- high Reynolds number flow separation has been worked on a lot more than low Reynolds number separation. This may be a good place to start:

http://en.wikipedia.org/wiki/Airfoil
 

Related to Calculating Flow Separation Point

1. What is flow separation point?

Flow separation point is a term used in fluid dynamics to describe the point at which the boundary layer of a fluid flow detaches from the surface of an object. This typically occurs when the flow encounters a change in surface curvature or a sharp edge.

2. Why is it important to calculate the flow separation point?

Calculating the flow separation point is important because it can help engineers and scientists understand the behavior of a fluid flow over an object. This information is crucial for designing efficient and aerodynamic structures, such as airplanes or cars, and can also be used to optimize the performance of turbines and other machinery.

3. How is the flow separation point calculated?

The flow separation point is typically calculated using computational fluid dynamics (CFD) software or through physical experimentation. CFD involves solving complex equations to simulate the behavior of a fluid flow, while physical experimentation may involve using smoke or dye to visualize the flow over an object and determining the point at which the boundary layer detaches.

4. What factors influence the flow separation point?

The flow separation point can be influenced by a variety of factors, including the shape and size of the object, the speed and viscosity of the fluid, and the angle of attack (the angle at which the fluid flow meets the object). Surface roughness, turbulence, and pressure gradients can also affect the flow separation point.

5. How can the flow separation point be controlled?

The flow separation point can be controlled through various methods, such as changing the shape of the object, adding turbulators or vortex generators, or manipulating the flow using suction or blowing techniques. These methods can help delay the separation of the boundary layer and improve the overall aerodynamic performance of the object.

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