Dynamics of Fluid Flow - Introduction

• The science that considers the forces causing flow also is known as dynamics of fluids/kinetics of

fluids.

• The fundamental transport phenomena associated with the motion of fluid are:

1. mass transport

2. heat transport

3. momentum transport.

Mass Transport

• All fluid motions satisfy the principles of conservation of matter.

• A homogeneous fluid is the one which exists throughout the region of interest as a single species.

• Non-homogeneous fluids are characterized by variation in the amount of one substance relative to

another from point to point. A canal carrying sediment laden water is an example of non-

homogeneous, two-phase flow. In case of non-homogeneous fluid, the principle of conservation of

matter must be satisfied for each component.

Heat Transport

• It deals with transport of heat by fluid.

• In this principle of conservation of energy (known as the first law of thermodynamics) is the basic

principle.

Momentum Transport

Momentum transport phenomena are of interest in fluid mechanics since they deal with mechanics of

fluid resistance, shear stresses and propulsion and forces on immersed bodies. Newton’s second law

of motion provides the fundamental relation between resultant of forces and time rate of change of its

momentum.