Engr Help

Finite Volume Analysis: Selection of Control Surface or Surfaces

Guidelines in Selecting the Control Surface or Control Surfaces

for your Finite Volume Analysis

Pick a control surface that borders sections where mass flux enters and

leaves the control surface. You may need more than one control surface.

Pick a control surface that includes surface forces such as pressure forces

and externally applied forces such those of restraint.

Construct a few streamlines as needed. Then apply Bernoulli's equation

to calculate the change in pressure along each streamline (perhaps from the

entry to the exit of the control surface). Keep in mind that pressure force

is the product of pressure time area.

Pick a control surface that includes body forces within the control volume

such as weight of the fluid within the control volume.

Pick more than one control surface in cases where pressure forces change

along the length of the application or where fluid velocity changes as a

result of changing cross-section.