Piecewise function to model time-dependant BC

April 5, 2006, 03:03

Hi

I am in the need to model the flow of blood passing through the coronary arteries. The inlet BC should be pressure driven by a typical Aortic Pressure Waveform which is a very oddly shaped function of Pressure vs. Time as some parts are linear and some quadratic or higher order.. it would be more accurate to model it as a piecewise function.

I need to know how to define piecewise functions in CEL expressions to model the time-dependant pressure at the inlet for this transient analysis.

Thanks

April 5, 2006, 03:09

1)Make use of the step function. You can turn on/off an equation on a particular time range.

2)Just another suggestion. Create a 2D data with time & pressure and then import it to Pre using User Function.

April 6, 2006, 11:00

Thanks

It seems that your 2nd suggestion was better and quicker..

April 5, 2006, 03:03	Piecewise function to model time-dependant BC	#1
Ramses Galaz Guest Posts: n/a	Hi I am in the need to model the flow of blood passing through the coronary arteries. The inlet BC should be pressure driven by a typical Aortic Pressure Waveform which is a very oddly shaped function of Pressure vs. Time as some parts are linear and some quadratic or higher order.. it would be more accurate to model it as a piecewise function. I need to know how to define piecewise functions in CEL expressions to model the time-dependant pressure at the inlet for this transient analysis. Thanks

April 5, 2006, 03:09	Re: Piecewise function to model time-dependant BC	#2
TB Guest Posts: n/a	1)Make use of the step function. You can turn on/off an equation on a particular time range. 2)Just another suggestion. Create a 2D data with time & pressure and then import it to Pre using User Function.

April 6, 2006, 11:00	Re: Piecewise function to model time-dependant BC	#3
Ramses Galaz Guest Posts: n/a	Thanks It seems that your 2nd suggestion was better and quicker..

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