# Which Algorithm???

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 August 6, 2003, 10:01 Which Algorithm??? #1 Ted Crilly Guest   Posts: n/a Hello there I hope you are well! I have a question for you - maybe you can help me. I have thought about a problem i would like to model using CFD. I have a big open space that has a large glass facade, the facade gets very hot in summer, to cool the space it is suggested to use a forced convection system to blow cool air at the facade surface and thus reduce the radiant effects of heat exchange. If my surface boundary is set to 50degC and i direct a large stream of cold air at say 14degC, this surface boundary will reduce in temperature by some amount, i.e. the large thermal buoyancy effect from the hot surface will reduce in time over a short period Does my Steady State simulation using the simple algorithm take this into account or not? should it be a transient run with PISO algorithm? when using Star If not how would I set up such a problem? - does it need to be a transient run? will i need to change the boundary temperatures at increment Thanks for any help offered Regards -Ted

 August 6, 2003, 11:36 Re: Which Algorithm??? #2 steve Guest   Posts: n/a If you don't care how long it takes to cool anything off than run it steady-state. With steady-state you will get the final equilibrium answer but not the path to get there. If you want to know what the temperature is at 1 second or 2 seconds or 10 seconds after you turn on the cold air, then you have to run transient.

 August 6, 2003, 12:01 Re: Which Algorithm??? #3 Ted Crilly Guest   Posts: n/a thanks for this advice steve