Heat Transfer

Computer Simulations and Thermal Design 391

indoors and sky, ground, and building temperatures for equipment operat-

ing outdoors. The atmospheric radiation described in Chapter 13, Section

13.4 can be accounted for in thermal simulation if the temperatures of the

computational surfaces representing the sky are set to the appropriate sky

temperature.

•  Flow Type

The ow inside and around the electronic system under thermal simulation

may be laminar, turbulent, or mixed. However, none of the commercial ther-

mal simulation tools is able to determine whether a ow is locally laminar,

turbulent, or in transition. Therefore, the user needs to specify the ow type

in advance as a global parameter. A good rule of thumb for electronic sys-

tems is ...