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Bernoulli's principle is a key concept in fluid dynamics that relates pressure, density, speed and height. Bernoulli's principle states that an increase in the speed of a parcel of fluid occurs simultaneously with a decrease in either the pressure or the height above a datum. [1]:
The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. [1] [2] [3] The Doppler effect is named after the physicist Christian Doppler, who described the phenomenon in 1842.
The mass flow rate for a compressible fluid will increase with increased upstream pressure, which will increase the density of the fluid through the constriction (though the velocity will remain constant). This is the principle of operation of a de Laval nozzle. Increasing source temperature will also increase the local sonic velocity, thus ...
The choked velocity is a function of the upstream pressure but not the downstream. Although the velocity is constant, the mass flow rate is dependent on the density of the upstream gas, which is a function of the upstream pressure. Flow velocity reaches the speed of sound in the orifice, and it may be termed a sonic orifice.
In fluid dynamics, dynamic pressure (denoted by q or Q and sometimes called velocity pressure) is the quantity defined by: [1] = where (in SI units): q is the dynamic pressure in pascals (i.e., N/m 2, ρ (Greek letter rho) is the fluid mass density (e.g. in kg/m 3), and; u is the flow speed in m/s.
A compressor increases the pressure of a fluid passing through it, so that the exit pressure is higher than the inlet pressure. Due to this property, compressors are used in a wide range of machines, such as refrigerators , cars, jet engines and industrial processes.
Whenever a gas is forced through a tube, the gaseous molecules are deflected by the tube's walls. If the speed of the gas is much less than the speed of sound, the gas density will remain constant and the velocity of the flow will increase.
As the flow speed increases (Reynolds number, Re) the frequency slowly climbs (nearly constant Strouhal number, St) but then the frequency jumps up abruptly to a higher stage. As the flow speed is later decreased, the frequency slowly decreases but then jumps down abruptly to a lower stage. This pattern is called a hysteresis loop.