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remslie14-Alexandrite
14-Alexandrite
April 2, 2012
Question

Solve Block beginner basics

  • April 2, 2012
  • 1 reply
  • 3545 views

I have a problem with a Solve Block. I wish to solve a system on nonlinear equations for the Stokes Wave Equation using "given" and "find" notation.

My first attempt at what seems to be a straight forward problem comes up with an "undefined variable" which I cannot seem to rectify. Experienced users will I am sure pick the error at light speed and help me out .

Thanks Ross

1 reply

A
AlanStevens19-Tanzanite
19-Tanzanite
April 2, 2012

See attached.

Alan

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remslie14-AlexandriteAuthor
14-Alexandrite
April 2, 2012

Alan, Thanks for your fast response and assistance to correct the sheet. The fact that lambda was set too high I acknowledge is a problem which I suspect I would have found if other underlying issues were not present. When you put lambda >1 in your sheet the program at least gives you a hint where the problem is in the error message.

When I set Lambda >0 in my sheet it still gives an undefined error so there are other problems.

Your solution makes all the B and C coefficients a function of "k", which I understand and clearly solves the problem, but I guess I am missing a fundamental point in that I thought the solver would take the guessed values of L and lambda and evaluate k and then the SS and CC equations followed by values for L and lambda and do this in an iterative fashion until a comnverged solution was obtained. Any comment on flaws in my logic here would be appreciated.

Cheers

ross

A
AlanStevens19-Tanzanite
19-Tanzanite
April 3, 2012

Your logic is basically ok, but you then have to solve for all the parameters - see attached. I felt this was unnecessarily cumbersome.

Incidentally, there is something strange about the way you've constructed B33, B35, C1 etc. I've replaced them with B.33, B.35, C.1 etc.

Alan

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