Staility – I : Chapter 2

8. A tank has a triangular bulkhead, apex upwards. Its base is 14m and its sides, 15m each. It has a circular inspection hole of radius 0.5m the centre of a manhole 0.8m above the base and 1.6 from one corner. Find the thrust on the manhole cover when the tank contain oil of RD 0.95 to a sounding of 10m.(Assume π to be 3.1416).

Solution:

Base = 14m , Sides = 15m , Depth of the oil = 10m

Pressure = (depth x density)
             =  (10 – 0.8 x 0.95)
            = 8.74 t/m²

Area of the circle = π r²
                 = (3.1416 x 0.5 x 0.5)
                 =0.7854m²

Thrust = (P X A)
          =( 8.74 x 0.7854)
          = 6.864 t.