Creating Field function combining Ramp Functions

SimulatorMaster · May 17, 2020, 13:31

Hello there,

I m trying to create a ramp function for my velocity inlet; however Im having a hard time.

For example, my velocity will start at 30m/s, accelerate up to 40m/s then decrease to 20m/s, and vice versa. The equation I am using is the equation of motion (Vf=Vi+a*time).

I have tried writing (0<=$Time<2) ? 'The EQN.1' : (2<=$Time<3) ? 'The EQN2.'

I have the data yet I do not know how to write it in StarCCM and join all these together.

Thank you.

cwl · May 17, 2020, 22:30

Instead of crazy syntax-based nested conditions - I'd suggest external .csv-table (Time-Velocity) and interpolateTable() function with LINEAR option.

SimulatorMaster · May 28, 2020, 15:28

Sorry I forgot to answer =/. I did find the necessary syntax yet I also learned how to insert tables from Excel as well. It is indeed way easier that way thank you!

Best regards..

May 17, 2020, 13:31	Creating Field function combining Ramp Functions	#1
SimulatorMaster New Member Onur Join Date: Dec 2018 Location: Turkey Posts: 25 Rep Power: 7	Hello there, I m trying to create a ramp function for my velocity inlet; however Im having a hard time. For example, my velocity will start at 30m/s, accelerate up to 40m/s then decrease to 20m/s, and vice versa. The equation I am using is the equation of motion (Vf=Vi+a*time). I have tried writing (0<=$Time<2) ? 'The EQN.1' : (2<=$Time<3) ? 'The EQN2.' I have the data yet I do not know how to write it in StarCCM and join all these together. Thank you.

May 17, 2020, 22:30		#2
cwl Senior Member Chaotic Water Join Date: Jul 2012 Location: Elgrin Fau Posts: 437 Rep Power: 18	Instead of crazy syntax-based nested conditions - I'd suggest external .csv-table (Time-Velocity) and interpolateTable() function with LINEAR option. SimulatorMaster likes this.

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May 28, 2020, 15:28		#3
SimulatorMaster New Member Onur Join Date: Dec 2018 Location: Turkey Posts: 25 Rep Power: 7	Sorry I forgot to answer =/. I did find the necessary syntax yet I also learned how to insert tables from Excel as well. It is indeed way easier that way thank you! Best regards..