Compressible versus Incompressible Flow

Compressible versus Incompressible Flow

A flow is classified as being compressible or incompressible, depending on the level of variation of density during flow. Incompressibility is an approximation, in which the flow is said to be incompressible if the density remains nearly constant throughout. Therefore, the volume of every portion of fluid remains unchanged over the course of its motion when the flow is approximated as incompressible. The densities of liquids are essentially constant, and thus the flow of liquids is typically incompressible. Therefore, liquids are usually referred to as incompressible substances. A pressure of 210 atm, for example, causes the density of liquid water at 1 atm to change by just 1 percent. Gases, on the other hand, are highly compressible. A pressure change of just 0.01 atm, for example, causes a change of 1 percent in the density of atmospheric air.

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Fluid Kinematics

Fluid Kinematics Fluid Kinematics deals with the motion of fluids such as displacement, velocity, acceleration, and other aspects. This topic is useful in terms of the exam and the knowledge of the candidate. Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces the cause the motion. Types of Fluid Flows Fluid flow may be classified under the following headings; Steady & Unsteady Flow Uniform & Non-uniform Flow Steady uniform flow Conditions do not change with position in the stream or with time. E.g. flow of water in a pipe of constant diameter at a constant velocity. Steady non-uniform flow Conditions change from point to point in the stream but do not change with time. E.g. Flow in a tapering pipe with the constant velocity at the inlet. Unsteady uniform flow At a given instant in time the conditions at every point are the same but will change with time. E.g. A pipe of constant diameter connecte

THE NO-SLIP CONDITION

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Fluid mechanics

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