What is hydraulic diameter and reference value?
 

Hello, can anybody tell me what is hydraulic diameter? if i am simulating a 2 dimensional air flow simualtion around a 4.465m length and 1.42m heigh car in a 60 x 35 meter square wind tunnel, what hydraulic diameter should i set? what are the area and length values should i set in the reference value? thanks.

HELP please! urgent.
 

Hello, can anybody tell me what is hydraulic diameter? if i am simulating a 2 dimensional air flow simualtion around a 4.465m length and 1.42m heigh car in a 60 x 35 meter square wind tunnel, what hydraulic diameter should i set? what are the area and length values should i set in the reference value? thanks.