Centre of Pressure and Centroid Fluid Mechanics

In summary, the problem asks for the calculation and plotting of the distance between the centroid and centre of pressure for a window installed at a depth of 50m in seawater with atmospheric pressure on the other side. This can be done using the given equations and considering the dimensions and properties of the window.
  • #1
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Homework Statement



a 2m by 4m window is to be installed under water at a depth of 50 m with seawater on one side and atmospheric pressure on the other. Calculate and plot the distance between the centroid and the centre of pressure starting from when the window is installed at surface such that 1m is above the water until the bottom of the window is flush with the bottom of the enclosure.

Homework Equations



y'cp=density*sin(theta)*I_xx/P_cg*A

I_xx=B*L^3/12

The Attempt at a Solution



so this is a pretty confusingly worded questiona nd I'm not even entirely sure what it's asking for

the centroid would exist at 2m,1m relative to the bottom left corner of the window
 
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  • #2
the centre of pressure would be at the same x coordinate and at a depth of 50m. I'm assuming we need to calculate the distance between the two points for different depths of the window since it's asking for a plot? for that we need to use the equation given above, where: y'cp = distance between the centroid and centre of pressuredensity = density of seawater theta = angle of window with respect to horizontal I_xx = second moment of area of the window P_cg = atmospheric pressure A = area of window B = width of window L = length of window so we can calculate the distance between the centroid and centre of pressure by plugging in the values and solving the equation y'cp = density*sin(theta)*I_xx/P_cg*Ay'cp = (density)*sin(theta)*(B*L^3/12)/(P_cg)*(B*L)y'cp = (density)*sin(theta)*(L^2/12)/(P_cg)then we can plot the distance between the centroid and centre of pressure as a function of the depth of the window.
 

Related to Centre of Pressure and Centroid Fluid Mechanics

1. What is the difference between Centre of Pressure and Centroid in Fluid Mechanics?

The Centre of Pressure is the point on a submerged object where the resultant force due to fluid pressure acts. It is a single point that represents the combined effect of all the individual pressure forces on an object. On the other hand, the Centroid is the centre of the geometric shape of an object. In fluid mechanics, it is the point where the weight of the object can be considered to act.

2. How can the Centre of Pressure and Centroid be determined experimentally?

The Centre of Pressure can be determined experimentally by using a pressure sensor placed at different locations on a submerged object. The location where the pressure sensor reads the highest value is the Centre of Pressure. The Centroid can be determined by balancing the object on a pivot point and marking the point where the object stays balanced. Alternatively, it can also be calculated using mathematical formulas based on the shape of the object.

3. How do the Centre of Pressure and Centroid affect the stability of an object in fluid?

The Centre of Pressure and Centroid play a crucial role in determining the stability of an object in fluid. If the Centre of Pressure is above the Centroid, the object will be unstable as the weight of the object will tend to rotate the object in the fluid. On the other hand, if the Centre of Pressure is below the Centroid, the object will be stable as the weight of the object will tend to bring the object back to its original position.

4. Can the Centre of Pressure and Centroid change in different fluid mediums?

Yes, the Centre of Pressure and Centroid can change in different fluid mediums. This is because the density and viscosity of the fluid can affect the pressure distribution on the object, thereby changing the location of the Centre of Pressure. The Centroid can also change if the object's weight changes in different fluid mediums.

5. How are the Centre of Pressure and Centroid used in practical applications?

The Centre of Pressure and Centroid are used in various practical applications, such as designing stable ships and submarines, determining the stability of aircraft, and designing efficient hydrofoils. They are also used in designing dams and other structures to ensure their stability against fluid forces. In addition, the Centre of Pressure and Centroid are crucial in fluid mechanics experiments and simulations for understanding the behavior of objects in fluid.

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