Aerodynamics: Recirculation Zone Wake and Speed

In summary, Mach number and Reynolds number affect the length of the recirculation zone and wake for supersonic and hypersonic speeds.
  • #1
aero5682
18
0
How does speed effect the recirculation zone and wake for supersonic and hypersonic speeds? Does it get longer, wider?
Also this is for a blunt body like apollo reentering
 
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  • #2
Speed is not directly relevant. Mach number and Reynolds number will be the most important parameters. You might start there with your search.
 
  • #3
I thought I had searched for mach number, apparently I hadnt searched mach number or reynolds numbers effects on it. It seems like subsonically and transsonically mach number and reynolds number increase the length of the recirculation zone, and supersonically and hypersonically decrease the length, but nothing I found was very clear on it
 
  • #4
You'll just have to keep up the search. I don't know any of the details of wakes like that to give you any answers here. I just know the basic parameters that govern it.
 
  • #5
Ok, thanks. Ill move it to aerospace and see if anything comes up
 
  • #6
I meant to do your own independent research on it. Search Google scholar and look for papers. You likely won't find that answer by asking on here. It's fairly niche.
 
  • #7
Yeah it seemed like it. I don't think I am going to find it here. And I will be looking on google scholar and stuff. But it doest hurt to ask. I thought there might have been some well known rules like recompression shock angles or pressure differences or something, or mabey it was some well known thing, but it doesn't seem so
 
  • #8
There probably are rules of thumb at least to some degree, but the area is so specialized that it's not something that would typically be taught in any undergraduate fluids course or really any graduate courses. It's the sort of thing a researcher would learn from reading papers while conducting their research rather than in a classroom. Shoot, I even teach compressible flow courses and I don't know the answer to this off the top of my head. All I can tell you is that the inviscid phenomena like the shock angles are going to depend pretty much exclusively on the geometry and the Mach number, and the viscous phenomena like unsteadiness in the wake are going to be based on the Mach and Reynolds numbers.
 
  • #9
Hmmm, I wonder if since the recompression shocks and those shear layers seem to sort of bound the wake in, if calculating those angles might help, but the unsteadiness in the wake might effect it too. Looks like I have some research to do
 

1. What is aerodynamics?

Aerodynamics is the study of how objects move through air and the forces that act on those objects, including lift, drag, and thrust.

2. What is a recirculation zone?

A recirculation zone is an area of low pressure behind an object moving through air, where air flows back towards the object instead of moving away from it. This can create turbulence and increase drag on the object.

3. What is a wake in aerodynamics?

In aerodynamics, a wake is the region of disturbed air flow left behind an object in motion. It is caused by the object pushing air out of the way as it moves, and can have a significant impact on the aerodynamic properties of the object.

4. How does speed affect aerodynamics?

Speed has a significant impact on aerodynamics. As an object moves faster, the air molecules around it move faster as well, creating more turbulence and increasing drag. However, at a certain point, increasing speed can also reduce drag due to the formation of a laminar boundary layer.

5. How can recirculation zones and wakes be reduced?

Recirculation zones and wakes can be reduced by using aerodynamic design principles, such as streamlining and shaping the object to minimize turbulence and reduce drag. Additionally, adding features like fins or spoilers can help redirect airflow and reduce the size of the wake.

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