How do I write the statements for solving second-order ordinary differential equations with gPROMS?
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It’s not the second derivative with respect to time t! Please, fellow sailors, help out! For example, how should the equation be written for d^2p/dx^2=4! Thank you so much!
It seems a bit too difficult; I’m unable to help
Reply to 3# lbaizyh: Thank you again! Thank you for your attention! Thank you!
Probably few people on the forum have used gPROMS. Your formula seems quite simple; why not write it in analytical form?
I hope everyone can help figure out whether the original poster’s problem can be solved; I’ll give high scores to those who do
Reply to 6# lbaizyh Thank you! Great! What a kind person! I would like to ask you another question: Original message: Error P1001: Parameter T101.A*al must have a value set. Error P1001: Parameter T101.Radial must have a value set. Note: My UNIT is defined as such, and T101,A*al and Radial represent my axial and radial distribution ranges; I don’t understand why values need to be set for these distribution ranges!
Reply to 5# robinbird Thank you! Back then, I just wanted to know the sign of the second-order ordinary derivative; now that I’ve transformed it into a second-order partial derivative, new problems have arisen! Original statement: Error P1001: The parameter T101.A*al must have a value set. Error P1001: The parameter T101.Radial must also have a value set. Note: In my UNIT definition, T101, A*al, and Radial represent the axial and radial distribution ranges; I don’t understand why these distribution ranges need to have values assigned to them! Please provide some guidance
Reply to 7# YouxiuXun: This is the first time I’ve encountered a problem like yours. I suggest posting your simulation file so that others can help you look at it. Given my current level of expertise, I doubt I can be of any help to you, haha
Reply to 9# lbaizyh Oh! Thanks anyway!
Introduce a new variable z, set z = dp/dx, introduce this as a new equation, and rewrite the original equation at the same time. This is the method for reducing the index of differential equations.
Reply to 11# polyup: First of all, thank you for your enthusiasm! Reduce the power to what’s not necessary; the key issue is that I don’t know how to write that constant derivative in gPROMs ! Another issue is this: the error messages that occur during gPROMs execution are as follows: Error P1001: The parameter T101.A*al must have a value assigned to it. Error P1001: The parameter T101.Radial must also have a value assigned to it. Note: In my setup, T101, A*al, and Radial represent the axial and radial distribution ranges; I don’t understand why these distribution ranges need to have values assigned to them! Thank you very much!