Step CEL expression to specify initial temperature of a geometry
 

Hi guys,

I have 2 geometries attached with an interface between the bus front door and rear door. I need help in writing and applying a CEL expression which will specify the initial temperature of the outside geometry. I have the dimensions and details but i cant seem to get my expression right.

The aim is to SET the initial temperature for the Outside geometry to T=40C and T=20C for inside bus geometry.. OUTSIDE GEOMETRY DETAILS(min y = -1.219, max y =11.2255) (min x = -5.86206, max x =14.1379) (min y = 0, max y =7.60093

More picture are attached to help clarify my case. PLEASE HELP ME!!!!!!!!

Thanks in advance

Regards,

Are you familiar with the CEL "inside()@Locator" function ? Similar to the step function but uses mesh or physics entities, so you do not need

Let us say your mesh contains only two pieces: one for the interior, say MyInteriorMesh, and one for the exterior, say MyExteriorMesh. You can initialize the domain using the following expression

Temperature = 20 [C] * inside()@REGION:MyInteriorMesh + 40 [C] * inside()@REGION:MyExteriorMesh

Done!!

If your interior mesh is made of multiple meshes, say MyInterior1, MyInterior2, you can then write it as

Temperature = 20 [C] * (inside()@REGION:MyInterior1 + inside()@REGION:MyInterior2) + 40 [C] * inside()@REGION:MyExteriorMesh

Hope the above helps,

Thanks for your reply.

Hi Opaque thanks for your reply. Im still new at expressions in CFX. I applied the expression you recomemded i should try with the appropriate details but i receive this error anytime i apply the expression.

ERROR: Bad expression value 'Expression 1' detected in parameter 'Temperature' in object '/FLOW:Flow Analysis 1/INITIALISATION/INITIAL CONDITIONS/TEMPERATURE'.
CEL error:
Syntax error detected in the expression assigned to 'Expression 1'.
Successfully read 12 characters:
Temperature
then error detected at:
= 20 [C] * inside()@REGION:B280 + 20 [C] * inside()@REGION:B539
Details - Unexpected character.


Do you know why this is happening?

Regards,

Thanks for your help Opaque, I have figure it out

Regards, [emoji3]