Boundary Layer Thickness of Blunt Body

[roldy]

I am working on a hypersonic vehicle project and would like to calculate the boundary layer. The vehicle that I am studying is the Apollo re-entry capsule. I'm assuming a 2-D flow. Here's what I have done so far.

Calculate the local surface inclination angle at any point on the blunt body surface (heat shield).

Calculated the pressure coefficient, drag coefficient, pressure, and temperature of the surface.

Essentially what I'm wondering is how do you calculate the pressure and temperature distribution from the blunt surface to the shock wave? Both are a function of y(distance away from the blunt body surface).

 

[boneh3ad]

You will need to solve the compressible boundary layer equations. Luckily for you, the blunt edge of the Apollo capsules were spherical, so you can use the spherical (or I guess if you are doing 2-D, cylindrical) form of the boundary-layer equations.

 

[NatSusan]

Hi there! It sounds like you're making good progress on your hypersonic vehicle project. Calculating the boundary layer can be a complex task, but luckily there are some established methods that can help guide you.

One approach is to use the Blasius solution, which is a semi-empirical solution for the boundary layer equations. This solution assumes that the flow is laminar and incompressible, so it may not be directly applicable to your hypersonic vehicle project. However, it can still provide a good starting point for your calculations.

Another method is to use the Thwaites method, which is an extension of the Blasius solution to compressible flows. This method takes into account the effects of compressibility and can provide more accurate results for high-speed flows.

To calculate the pressure and temperature distribution from the blunt surface to the shock wave, you will need to use the conservation equations for mass, momentum, and energy. These equations can be solved numerically using computational fluid dynamics (CFD) software or by hand using a finite difference or finite volume approach.

In addition to these methods, you may also want to consider using experimental data or empirical correlations to validate your results. Good luck with your project!