Calculation of Pressure Forces on Submerged Rectangular Plates

Case 1: Vertical submerged plate at surface (simplest case)

The magnitude of the pressure force equals the pressure at the centroid of the plate times

the area of the plate. Let γ be the specific weight of the fluid. Then in case 1 the pressure

at the centroid of the plate is γ h. Let w be the width of the plate (into the paper). So the

total pressure force F_r on the plate is (γh)(2hw).

The location of the pressure force is at the “centroid” of the pressure prism. In this case, the

pressure force acts at a depth of (4/3) h.

Case 2 Calculation of Pressure Forces on a “Slanted” submerged plate at surface

The magnitude of the pressure force equals the pressure at the centroid of the plate times

the area of the plate. Let γ be the specific weight of the fluid. Then in case 2 the “pressure

at the centroid of the plate is γ h cos α. Let w be the width of the plate (into the paper). So

the total pressure force F_r on the plate is ( γh cos α ) (2hw).

Again the location of the pressure force, F_r is at the “centroid” of the pressure prism. In this case, the pressure force acts at a depth of [(4/3)] h cos α .

Click here to continue with other cases.

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