Homework 5

[Josh Duckett]

How did you all approach the shock wave problem? Did you do it the
way Hassan was talking about in class or the way the book talks about
it in iterations? I didn't really follow what Hassan was saying to do
and did it the book way but my pressure seemed high. Not sure of the
number I got - have to look when I get home - but it seemed too high.
Have you all gotten it worked out?

Josh

[Ashveen Tewarie]

I did the first problem according to Dr Hassan's instructions. I think
he wants us to do it that way because of the note he made on the HW
assignment sheet. What I did is use the eqns for equilibrium, eqn of
state and the other 4 eqns he provided during the lecture when we did
the shock wave stuff. From all these eqns I derived rho2 as function
of T. Two expressions can be derived for rho2(T) and you can make a
Matlab plot to determine their intersection. I am getting a
temperature of about 5800K at this moment. I have not calculated
pressue, alpha and enthalpy yet since I had MAE518 (Acoustic
Radiation) exam yesterday. I will finalize later on today.

I haven't got a chance yet to look at the second problem....

[Josh Duckett]

How did you find alpha for equilibrium equation?

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[Ashveen Tewarie]

Might be late, but since you're asking I'll try to explain what I
did...

From the energy eqn --e2 + (P/rho) + (0.5U^2)=a3-- you can easily
determine alpha(rho,T) since this eqn is linear in alpha. To do this
you will have to use the eqn of state also.

Now, substitute alpha(rho, T) in the momentum eqn--P+ rho*(U^2) =a2 in
order to determine rho(T) and make a plot for this.

You can also substitute alpha(rho,T) in the equilibrium eqn. to obtan
rho(T) and make a plot.
The intersection of both plots gives the required T and rho.

Almost all of the above eqns I did in Matlab.

Hope this helps.

[Ashveen Tewarie]

I will now start working on the 2nd problem which seems harder than
the first one since Q_el is a function of T for oxygen.

[Josh Duckett]

Ashveen

I've gotten my graded homework back and have tried to go back though and fix
it but I'm still having some problems. Can you send me a scan of your
Problem 1 so I can see an example worked out?

Thanks
Josh

Hope this helps.