Civil Engineering - Hydraulics - Discussion
Discussion Forum : Hydraulics - Section 4 (Q.No. 31)
31.
If H is the depth of water retained by a vertical wall, the height of centre of pressure above the bottom is
Discussion:
35 comments Page 1 of 4.
Hemanth said:
3 years ago
Traingle =H/2.
Rectangular=H/3.
Consider a rectangular plate of width b and height h is immersed in water.
h'= Depth of centre of gravity of rectangular plate from free surface = h/2.
Area = bh Moment of inertia through centre of gravity. IG = bh3/12.
h* = Distance of centre of pressure from the free surface of a liquid =( igsin^2@/ah')+h'
For vertical plane surface: θ = 90°
The distance of the centre of pressure from the base = h - 2h/3 = h/3.
Rectangular=H/3.
Consider a rectangular plate of width b and height h is immersed in water.
h'= Depth of centre of gravity of rectangular plate from free surface = h/2.
Area = bh Moment of inertia through centre of gravity. IG = bh3/12.
h* = Distance of centre of pressure from the free surface of a liquid =( igsin^2@/ah')+h'
For vertical plane surface: θ = 90°
The distance of the centre of pressure from the base = h - 2h/3 = h/3.
(1)
Harry said:
6 years ago
For vertical wall - from the top - 2h/3 , from bottom - h/3.
For a triangle with the base at free surface - h/2.
For a triangle with the apex at free surface - 3h/4.
For circle touching free surface - 5h/8.
For a triangle with the base at free surface - h/2.
For a triangle with the apex at free surface - 3h/4.
For circle touching free surface - 5h/8.
Vatsal patel said:
9 years ago
H/2 answer is right because pressure acting at the vertical wall so that half of that depth. But if dam (triangle) that time it's pressure acting at h/3.
Pinku said:
5 years ago
Apply the law of hydrostatic pressure. The pressure diagram will be traingle in which the hydrostatic force passes through the cg i.e h/3frm bottom.
(2)
Abdullah khan said:
4 years ago
H/2 is the correct answer. The question is related to the center of the vertical wall not to center of gravity or point of application.
(2)
Rahul said:
6 years ago
H/2 is correct because when depth is very high or not given then the centre of pressure is acting on the centre of gravity.
Krrish said:
9 years ago
H/3 is the answer, because pressure increase with depth of water then the pressure curve made in a triangular shape.
Vimesh said:
8 years ago
Not given that total pressure. Only center of pressure from water. Than h/2 is the right answer.
Nayan said:
8 years ago
It's center of pressure, H/2 to surface and H/2 to bottom.
And centroid is 2H/3 below surface.
And centroid is 2H/3 below surface.
Shahrukh said:
3 years ago
H/2 will be centroid and the Center of pressure is always below the CG.
So, H/3 is correct.
So, H/3 is correct.
(1)
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