Pressure Datum

Pressure Datum = <float> { atm | torr | cgs }

Description / Usage

This card is used to set a thermodynamic pressure datum on fluid or solid mechanics problems that calculate equations of state requiring a true value for the total pressure. The total pressure is then defined as the sum of a constant base thermodynamic pressure, specified by this card, and a variable hydrodynamic pressure calculated via the pressure unknown. Definitions of the input parameters are as follows:

<float>

Value of the thermodynamic pressure datum.

{ atm | torr | cgs }

Units of the float specified above.

Examples

Following is a sample card:

Pressure Datum = 1.0 atm

Technical Discussion

The value of this variable is stored in the unified problem description structure in cgs units. It is then used in consistency checks and as input into some equation of state routines, such as the ideal gas equation of state routine.