To investigate the validity of the formulas for resultant force on, and position of center of pressure of a vertical rectangular surface.

Hydrostatic Pressure & Center of pressure:

• Hydrostatic force is defined as the force exerted by the static liquid on any body or surface which is brought in contact with the standing water and the corresponding force per unit area is known as hydrostatic pressure.
  
• Center of pressure is the point of application of the resultant hydrostatic pressure.
  

Apparatus Required:

• Hydrostatic pressure and centre of pressure apparatus. loose weights.
  

Theory:

For the above apparatus, the plane subjected to hydrostatic force is vertical. The following formulae may be applied to give expressions for moment of the hydrostatic force about the knife- edge axis: –

1. Partial Immersion
   

1. Complete Immersion
   

Fig. 7.3

Procedure:

Method

1. Measure the dimensions a, b; d and I.
2. Level the apparatus by using the adjustable feet.
3. Adjust the counterbalance weight until the balance arm is horizontal.
4. Place a mass on the balance pan and fill the tank with water until the balance arm is horizontal. Note the water level (y) on the scale. Pour water over dry surfaces when filling the tank to reduce the surface tension.
5. Repeat the procedure for different masses and noting the corresponding water levels.
6. Take approximately 8 readings on the bottom scale and 6 readings on the top scale.
7. Verify previous readings by reducing the masses on the balance pan.

Observations:

1. y < d (Partial Immersion)
   

Table

a = 12 cmd = 10 cm

b = 7.5 cml = 30 cm

1. y > d (Complete Immersion)
   

Results & Comments:

0r