Expert: Paul Soderman - 11/20/2011

Question
QUESTION: Hi sir,

I am interested in doing a project on the supersonic inlet designs for my final year.I have a started a few tests on a particular axis-symmetric inlet design in the supersonic tunnel provided by my university.But the problem is I am not quite sure where I can head this project to? I need your suggestions for the best possible research topics in this subject

Thank you

ANSWER: AshokRaja - Supersonic inlet design has been studied for many years. The primary objective is to design the inlet and diffuser so as to obtain the minimum total pressure loss. This often includes the use of a center body spike or wedge that creates an oblique shock followed by a normal shock whereas a simple inlet without spike only has a normal shock. A single normal shock has large losses. So one question is - what geometry gives a combination of oblique and normal shocks that are optimum for your design ?  What if the spike were moveable. All this depends on Mach number, geometry and the location of the inlet on the aircraft. There are related issues such as non-axial inflow and separation, transition from subsonic to supersonic flow, boundary layer effects and so on.  I assume you have some type of Schlerein system to visualize the shocks. I remember doing something like this at Boeing when I was an intern in 1965, and the computer was in a big room down the street. I assume there are better tools now. Sounds like fun. Good luck.
Paul

---------- FOLLOW-UP ----------

QUESTION: Dear Sir,

Thank you for your response.It was greatly helpful in the further proceedings. Now that I am done with testing the model , I am planning to start my dissertation content. I would like to know your suggestions on the critical topics which I need to cover up in my dissertation work and also the wide spread areas in this subject which I can include as well.

Thank you

Answer
I am not sure what more I can add. Most dissertations include results that show how a technology performs compared to other published data and computational predictions. By performance the important elements would be pressure changes through the system, shock angles, flow separation, velocities or Mach number distributions and so on. Any new ideas or approaches would be especially good including measurement techniques. It is hard to be more specific without knowing what you have done or tried to do.
Paul