Del operator-Laplacian operator-Divergence Del operator ∇ = (∂/∂x,  ∂/∂y, ∂/∂z) Gradient is partial derivative of a function with respect to x or y or z ∂p/∂x is pressure gradient in x direction ∂p/∂y is pressure gradient in y direction ∂p/∂z is pressure gradient in z direction ∂v/∂x,  ∂v/∂y, and ∂v/∂z are velocity gradients. ∂V/∂x,  ∂V/∂y […]

FLUID MECHANICS-1- INTRODUCTION Definition of a fluid Fluid is a common name for a liquid, vapor and a gas.  (a) Liquids Liquids have definite volume but not definite shape. These do not fill the container fully. These are in-compressible and are heavy as compared to a gas.  (b) Vapor When liquid on heating changes phase […]

                 Mcq on cavitation ·         1. Cavitation is a process of (a) Liquid formation (b) Vapor formation (c) Neither vapor nor liquid formation (d) None ANS: (b) Cavitation is found in (a) An accelerated liquid flow (b) De-accelerated flow (c) Gas flow (d) None ANS: (a) The accelerated flow […]

Mcq ON WATER HAMMER The other name of water hammer is (a) Shock wave (b) Fluid blow (c) Water blow (d) None ANS: ( c) Water hammer is due to (a) Sudden change in internal energy (b) Sudden change in potential energy (c) Sudden change in molecular energy (d) None ANS: (d) Water hammer is […]

DRAG Drag is a force of resistance when a body is moving in water or air. In air, it is called aerodynamic drag. It is expressed in Newton’s. It is always against the thrust force. It opposes forward motion.  Drag force  is present in a moving fluid. It is found in fluid dynamics. It is a […]

WATER HAMMER Water hammer is also called a fluid hammer or Hydraulic Shock’ or a water blow.  It largely takes place in liquids but to a limited extent it can also be present in gases. It is a very high pressure wave created due to sudden change in momentum due to sudden stopping a moving […]

CAVITATION It is process of vapor formation  in an accelerated liquid  flow at a certain temperature. The accelerated flow is found in pumps and turbines etc. Due to acceleration, there is an increase in velocity. Thus, there is fall of static pressure resulting in low pressure below the saturation pressure of the liquid. These vapors […]

BERNOULLI ENERGY AND MOMENTUM EQUATIONS Bernoulli Equation The equation comes from Newton’s law of motion. Assumptions used in deriving Bernoulli’s equation: Flow is steady In compressible flow Non-viscous flow (ideal fluid with zero viscosity) No losses and no energy exchanges Further, Bernoulli’s equation states that “Total head of a flowing fluid is constant or total […]

INTERVIEW SHORT QUESTION ANSWERS–CENTRIFUGAL COMPRESSOR Explain slip factor and work input factor in a centrifugal compressor. Slip factor During the fluid flow through the impeller passage, there is a pressure difference and velocity difference between the leading and trailing faces of the impeller blades. There is relatively a high pressure and low velocity on the […]

INTERVIEW SHORT QUESTION ANSWERS ON FLOW MEASUREMENT Define circulation. How is it different from vorticity? Circulation Circulation is defined as line integral of the tangential velocity about a closed path (contour). It is a scalar quantity. Its symbol is ɼ. Vorticity It is the tendency of a fluid particle to rotate or spin at a particular point. Vorticity […]