Category: Fluid Mechanics And Hydraulic Machines

INTRODUCTION TO HYDRAULIC MACHINES Hydraulic machines are the devices that convert hydraulic energy into mechanical energy or mechanical energy into hydraulic energy. Hydraulic turbines are the basic prime movers which convert the hydraulic energy (in the form of pressure/kinetic energy) into mechanical energy. Pressure energy is developed due to head of water in the form…

The Bernoulli’s equation is an approximate relation between pressure, velocity and elevation, and is valid in regions of steady and incompressible flow where net frictional forces are negligible. Despite its simplicity, it has proven to be a very useful tool in fluid mechanics. The key approximation in the derivation of the Bernoulli equation is that…

The interaction of the static fluid with its surroundings is in the form of force, which is applied equally on all contact points. This force is the result of the pressure applied on a particular unit area. The pressure in the fluid is not constant throughout. The pressure in any body of fluid varies with…

Let h = Fall in height of liquid in tube, σ = Surface tension of liquid, and θ = Angle of contact between liquid and glass tube. Example 9.4: Calculate the capillary rise in a glass tube of diameter 2 mm when immersed vertically in (i) water, and (ii) mercury. Assume surface tension for water as 0.07 and for mercury as 0.5…

Let h = Height of liquid in tube, σ = Surface tension of liquid, and θ = Angle of contact between liquid and glass tube.

Example 9.2: The surface tension of water in contact with air at ambient temperature is 0.10 N/m. The pressure inside the water droplet is 0.03 N/cm2 greater than the outside pressure. Calculate the diameter of water droplet. Solution: Example 9.3: Find the surface tension in a soap bubble of 50 mm diameter when the inside pressure is 4…

Let σ be the surface tension of liquid, p be the pressure intensity inside the droplets and d be the diameter of droplets. Tensile force due to surface tension acting around the circumference of the liquid droplets will be equal to pressure force on the projected area.

Surface tension is the tendency of the surface of a liquid to behave like a stretched elastic membrane. There is a natural tendency for liquids to minimize their surface area. The obvious case is that of a liquid droplet on a horizontal surface that is not wetted by the liquid—mercury on glass or water on…

An ideal fluid has zero viscosity. Shear force is not involved in its deformation. An ideal fluid must be incompressible. Shear stress is zero irrespective of the value of ∂u/∂y. Bernoulli equation can be used to analyse the flow. Real fluids having viscosity are divided into two categories, namely, Newtonian and non-Newtonian fluids. In Newtonian fluids a linear…

Viscosity, μ is a property of fluid which offers resistance to sheer deformation. Different fluids deform at different rates under the same shear stress. Fluid with a high viscosity, such as lubricant oil deforms more slowly than fluid with a low viscosity such as water. In any fluid flow, layers move at different velocities and the fluid’s…