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DragForce_SemiTruck

 

 

Procedure DragForce_Pickup returns the drag force for a typical semi-trailer truck without fairing.  Fairings may reduce the drag coefficient by 20%

 

Inputs

Fluid$ - the name of any fluid in the EES data base.  Fluid$ may be a string constant or a string variable.

T - temperature in the defined unit system [F,C,R,K]

P - pressure in the defined unit system [Pa,kPa,bar,MPa,psia,atm]

v - free stream fluid velocity in [m/s, ft/min]

A - the frontal area of the vehicle in [m^2] or [ft^2]

      (A can be estimated as the product of height and width of the vehicle multiplied by 0.85.)

 

Outputs

F_d  - drag force per unit length [N or lbf]

C_d  - drag coefficient {optional}

Re - Reynolds number {optional}  {value is not needed for the calulation and the result returned is an estimate}

 

This procedure calls function DragCoefficient_SemiTruck to obtain the drag coefficient.

 

Example:

$UnitSystem SI C kPa 

Fluid$='Air'

T=25 [C]

P=Po#

v=10 [m/s]

A=9.4 [m^2]

CALL DragForce_SemiTruck(Fluid$,T,P,v,A:F_d,C_d,{Re}) 

 

{Solution:

C_d=0.8 

F_d=445.2 [N]

}

 

 

Index