Momentum Balance across Ejector

Momentum Balance across Ejector - Solve command ambiguity - Сообщения

#1 Опубликовано: 23.06.2018 02:34:35
usamakhan

usamakhan

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In the attached problem I am having x2 issues. The first thing is that if I assign Mhp to 17 elements & then try to solve (built in command) the array of 100 elements is returned? Secondly using Solve (Maxima) I get the required answer (17 element array) but only the last element has the answer (rest are zero)?

Objective is to plot D1 values for given set of Mhp values

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#2 Опубликовано: 23.06.2018 06:21:33
Martin Kraska

Martin Kraska

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There were some issues in your file.
1. your expression MomentumBalance... isn't ready for vector arguments. V[2*Mhp evaluates to the scalar product between two vectors. This probably isn't what you want.
2. The last loop iterates over just one element.
3. Data is constantly overwritten by the last entry.
4. In the first iteration of the loop you overwrite your range of value with the first element.
5. Solve() returns a boolean equation. In order to convert this into an assignent, you can use the substitution function at()

The solution is to provide a separate variable holding the range of values and then iterate Mhp over this range.

If you just want the plot, you can use the Maxima Draw function implicit().

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frapuano 23.06.2018 14:29:00
#3 Опубликовано: 23.06.2018 09:21:58
Вячеслав Мезенцев

Вячеслав Мезенцев

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frapuano 23.06.2018 14:29:00
#4 Опубликовано: 23.06.2018 13:37:01
usamakhan

usamakhan

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Wrote

5. Solve() returns a boolean equation. In order to convert this into an assignent, you can use the substitution function at()



:d thanks for this marvelous explanation. However I failed to comprehend why the built in solve command returns 100 elements array? Doesn't it work similarly to Maxima Solve?

uni, thanks but how do I dynamically convert the expression MomentumBalance to the one you have used to plot. I mean I cannot find something like this which will result in the right construct to be used by XYPlot

f(x,y):= RHS(expr) - LHS(expr)

#5 Опубликовано: 23.06.2018 14:11:58
Вячеслав Мезенцев

Вячеслав Мезенцев

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Try this.

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#6 Опубликовано: 24.06.2018 10:18:11
Jean Giraud

Jean Giraud

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Wrote

thanks for this marvelous explanation. However I failed to comprehend why the built in solve command returns 100 elements array? Doesn't it work similarly to Maxima Solve?

uni, thanks but how do I dynamically convert the expression MomentumBalance to the one you have used to plot. I mean I cannot find something like this which will result in the right construct to be used by XYPlot

f(x,y):= RHS(expr) - LHS(expr)



1. Once you have Ejector in the two variables, recast as Uni did
2. Solve for an analytical solution ... via Maple
3. Recast/export

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