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carno June 22, 2005 02:41

input curve BC
Hi All,

I am doing exhaust manifold transient analysis with CHT.

I want to impose a BC which is time dependant. This can be achieved by tables or user subroutines. But my problem is that the input curve (obtained from expt) is highly complicated. (average outlet temperature from a IC engine comb chamber wrt time). So I can not put that in polynomial. So user subroutine option is ruled out. Now I can input that in table.

But after 92 entries in the table; star is not taking the table values. So I am not able to run the full transient analysis. Another disadvantage of table is that one can not put that in loop. Lets say I want to apply that BC in cycles over some duration. (depending on engine speed)



Jörn Beilke June 22, 2005 04:25

Re: input curve BC
Why not create some sort of table in the subroutine and interpolate the values between. You are not limited to polynoms in the subroutines.

carno June 22, 2005 05:03

Re: input curve BC
Thanks Jörn,

But if we create table the value of the variable will remain assigned to the specific time value. But the same value for that variable will appear in next cycle for different time value. How to achieve this? One solutionn is that; I have to offset (no of cycles occured*period of cycle) time value in table to get new time value and same variable value.

Kindly guide.


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