Velocity of propagation

Under vacuum, the velocity of propagation c of an electromagnetic wave is... 

For coaxial cables, the following electrical properties related to the dielectric constant of the core material and the dimensions determine the quaUty of the signal impedance, capacitance, attenuation, crosstalk, and time delay and velocity of propagation. 

Time Delay and Velocity of Propagation. Time delay is direcdy proportional to the square root of the dielectric constant and describes the time that it takes for a signal to travel through a cable. The lower the dielectric constant, the less time required for a signal to travel through a cable. 

Velocity of propagation is the speed of transmission in a cable as compared to the speed of transmission in air and is therefore expressed as a percentage. Since the velocity of propagation is inversely proportional to the square root of the dielectric constant of the core, a lower dielectric constant results in higher transmission speed (3). 

The velocity of current or voltage waves in any medium is called the velocity of propagation of electricity in that medium. The velocity of electromagnetic waves (electricity) through a conductor is a measure of line or conductor parameters through which it propagates and is represented by... 

V = velocity of propagation in km/s L(i - line or conductor mutual inductance in H/km Q = leakage capacitance of the same medium in F/km... 

Nominal voltage, Vr kVir.m.s.) Conductor Type Line inductance Xl O/km Line capacitance R(0 O/km c - Velocity of propagation u- Wavelength X = U/f km... 

Velocity of propagation of electromagnetic waves — 3 X I o km/s (more accurate values are determined in Table 24.1 (b) for the line parameters considered). 

The sound speed c, m s , is the velocity of propagation of the pressure variations. This depends on the physical properties of the medium and increases with the density of the medium. In air, for example, it is. 344 m s, while in water, 1410 m s and in concrete, 3000 m s . The elapsed time between successive compressions is called the period time T. 

Burning velocity The velocity of propagation of a flame burning through a flammable gas-air mixture. This velocity is measured relative to the unbumed gases immediately ahead of the flame front. Laminar burning velocity is a fundamental property of a gas-air mixture. 

Fortpflanzung, /. propagation, transmission, communication reproduction. Fortpflanzungs-gesehwindigkeit, /. velocity of propagation (or of transmission), -riehtung, /. direction of propagation (or of transmission). ... 

Br = ratio of pipe diameter (I.D.) to wall thickness a , = velocity of propagation of elastic vibration in the discharge pipe, ft/sec... 

This maximum velocity of a compressible fluid in a pipe is limited by the velocity of propagation of a pressure wave that travels at the speed of sound in the fluid [3]. This speed of sound is specific for each individual gas or vapor or liquid and is a function of the ratio of specific heats of the fluid. The pressure reduces and the velocity increases as the fluid flows downstream through the pipe, wdth the maximum velocity occurring at the downstream end of the pipe. WTien, or if, the pressure drop is great enough, the discharge or exit or outlet velocity will reach the velocity of sound for that fluid. 

Newton (1686) first calculated the velocity of propagation of a compressional wave of permanent type in an elastic medium, and arrived at the general formula ... 

When the pressure at some point in a fluid is changed, the new condition takes a finite time to be transmitted to some other point in the fluid because the state of each intervening element of fluid has to be changed. The velocity of propagation is a function of the bulk modulus of elasticity e, where e is defined by the relation ... 

Reduction of P2 initially results in an increase in G. G increases until the gas velocity at the outlet of the pipe just reaches the velocity of propagation of a pressure wave ( sonic velocity ). This value of P2 will be denoted by Pv. 

It has been seen in deriving equations 4.33 to 4.38 that for a small disturbance the velocity of propagation of the pressure wave is equal to the velocity of sound. If the changes are much larger and the process is not isentropic, the wave developed is known as a shock wave, and the velocity may be much greater than the velocity of sound. Material and momentum balances must be maintained and the appropriate equation of state for the fluid must be followed. Furthermore, any change which takes place must be associated with an increase, never a decrease, in entropy. For an ideal gas in a uniform pipe under adiabatic conditions a material balance gives ... 

In the so-called "wrinkled flame regime," the "turbulent flame speed" was expected to be controlled by a characteristic value of the turbulent fluctuations of velocity u rather than by chemistry and molecular diffusivities. Shchelkin [2] was the first to propose the law St/Sl= (1 + A u /Si) ), where A is a universal constant and Sl the laminar flame velocity of propagation. For the other limiting regime, called "distributed combustion," Summerfield [4] inferred that if the turbulent diffusivity simply replaces the molecular one, then the turbulent flame speed is proportional to the laminar flame speed but multiplied by the square root of the turbulence Reynolds number Re. ... 

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