Oblique Shock Angle Calculation

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Discussion Overview

The discussion revolves around calculating the oblique shock angle (beta) for a supersonic airfoil using MATLAB. Participants are exploring methods to derive this angle based on parameters such as angle of attack, Mach number, and airfoil geometry. The conversation includes technical challenges related to the implementation of the calculation in MATLAB and alternative software options.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant is seeking an equation to calculate the oblique shock angle (beta) and expresses difficulty in finding a suitable formula.
  • Another participant suggests using MATLAB to solve for beta and mentions having the relevant equation in a textbook.
  • Some participants note that the equation for beta is complex and may be split into multiple parts, complicating the calculation.
  • There are suggestions to use numerical methods such as iteration or MATLAB's fsolve command to find beta, indicating a preference for numerical solutions over symbolic ones.
  • Participants express varying opinions on software tools, with some advocating for Maple while others prefer Mathematica, highlighting a debate on the best computational tools for this task.
  • A later post reiterates the initial request for help with the MATLAB program, indicating ongoing interest in collaboration or assistance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method to calculate the oblique shock angle, with multiple approaches and software preferences being discussed. The complexity of the equations involved and the lack of a straightforward solution contribute to the unresolved nature of the discussion.

Contextual Notes

Participants mention the absence of the symbolic math toolbox in MATLAB as a limitation, which affects their ability to solve the equation for beta directly. The discussion also reflects varying levels of familiarity with different computational tools and their capabilities.

Who May Find This Useful

This discussion may be useful for individuals interested in computational fluid dynamics, specifically those working with supersonic airfoils and seeking methods for calculating oblique shock angles using MATLAB or alternative software.

Freyster98
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I'm trying to write a MATLAB .m-file that will calculate the lift and drag on a supersonic airfoil using only the angle of attack, mach number, and geometry of the airfoil. I'm getting stuck on the oblique shock angle calculation because I cannot find an equation that is solved for the shock angle (beta). Does anyone know what equation I can use for this? Other than that, I think I'm all set. Any help you can give would be greatly appreciated. Thanks!
 
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rugabug said:
http://upload.wikimedia.org/math/2/7/b/27b8202d60430e48b08cf5b6498c1097.png
You can use MATLAB to solve for beta or if I remember when I get home I have the equation for beta in a textbook.

I have that equation, but I just found out I don't have the symbolic math toolbox for MATLAB and that's why I couldn't solve the equation for beta. I used Maple to solve for beta and got a ridiculously long result.
 
Freyster98 said:
I have that equation, but I just found out I don't have the symbolic math toolbox for MATLAB and that's why I couldn't solve the equation for beta. I used Maple to solve for beta and got a ridiculously long result.
The equation in my book is ridiculously long. They actually split it into 3 equations.
 
man u need to make an iteration using MATLAB i did it before and this is a code for it
 

Attachments

Or just use the freaking fsolve or solve commands to do it numerically, since I assume that is what you are supposed to do anyway.
 
Freyster98 said:
I have that equation, but I just found out I don't have the symbolic math toolbox for MATLAB and that's why I couldn't solve the equation for beta. I used Maple to solve for beta and got a ridiculously long result.


Symbolic Math Toolbox! That is really something i desire very much i wonder why they did not put the inverse laplace transform capability on MATLAB...
 
Use maple its just great
 
Maple is craptastic. Mathematica is a nicer package IMO.
 
  • #10
Freyster98 said:
I'm trying to write a MATLAB .m-file that will calculate the lift and drag on a supersonic airfoil using only the angle of attack, mach number, and geometry of the airfoil. I'm getting stuck on the oblique shock angle calculation because I cannot find an equation that is solved for the shock angle (beta). Does anyone know what equation I can use for this? Other than that, I think I'm all set. Any help you can give would be greatly appreciated. Thanks!

i need this your program.can you help me? if it possible for you please send that to me.thanks
mhd.hadipour@yahoo.com
 

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