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Calculation of Pressure Forces on Submerged Rectangular Plates

Step 3: Calculate the total pressure force, F_R, acting on the plate. The total pressure force is

the pressure at the centroid of the plate time the area of the plate. F_R = γ(d + h cos α) (2wh).

Step 4: Calculate the pressure force F₁ acting over ABCD and the pressure force F₂ acting over

the triangular distribution ADE. Here F₁ = γd (2hw) and F₂ = (γh cos α)(2hw) .

Step 5: Locate pressure forces F₁ and F₂by identifying the centroid of ABCD and the centroid

of ADE. The centroid for F₁ is at h and the centroid for F₂ is at (4/3)h. See the figure above.

Step 6: Calculate the location of the total pressure force, F_R, acting on the plate by summing moments

of F₁ and of F₂ about point B using the principle of first moments. i.e.

F_R(sbar) = F₁ h + F₂ ((4/3)h where F₁ = γd(2hw) and F₂ = γhcos α 2hw)

The center of pressure CP is at sbar = [ F₁ h + F₂ ((4/3)h] / F_R . See the figures above and below.

sbar = location of center of pressure, CP. Click here for examples.