turbulence energy

turbulence energy

[′tər·byə·ləns ‚en·ər·jē]
(fluid mechanics)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
Mentioned in ?
References in periodicals archive ?
Turbulence flow modelling include turbulence energy transport equation:
(2), there exist one-dimensional turbulence energy spectra, and also second- and third-order structure functions, having different, but analytically related, universal constants (e.g., Pope 2000), which form the theoretical basis for EDR retrieval techniques.
This paper aims to reduce vibration and noise by developing a novel rotating-sleeve distributing-flow system and analyzing the relationship between turbulence energy, velocity, and working pulsation through CFD simulation.
Although some differences from the target turbulence conditions were found, all spectra measured behind the RTS were found to be within the range of turbulence energy measured during the on-road campaign.
During the first several hours represented in Figure 15, when the typhoon has not yet arrived at the bridge site, the fluctuation energy of the wind remains low; the turbulence energy then increases sharply with the arrival of the typhoon at the bridge site and remains at a high level until the typhoon has passed the bridge site, after which the turbulence energy recovers to a relatively low level.
As opposed to pipe flows, rectangular and square channel flows, even in case of unladen flows, are considerably anisotropic with respect to the components of the turbulence energy, which is vividly expressed near the channel walls and corners being notable as for the secondary flows.
where: t--time; [rho]--density; [PHI]--dependent variable, as a moment to the unit of mass, turbulence energy, its dissipation rate; when [PHI] = 1--continuity equation; [bar.v]--velocity vector; [GAMMA]--exchange coefficient of the variable [PHI]; [S.sub.[PHI]]--flow (source) term to variable [PHI].
It is easy to see that for the turbulent flows with [OMEGA] [not equal to] 0 the turbulence energy (understood here as the energy of velocity fluctuations) K = 1/2 ([v'.sup.2] can be naturally decomposed as follows:
Nomenclature V - Fluid velocity (m/s) [D.sub.h] - Hydraulic diameter (m) A - Area of collecting fields (m2) K - Face permeability (m/s) [K.sub.loss] - Empirical loss coefficient I - Turbulence intensity k - Turbulence energy Re - Reynolds number P - Perimeter of collecting plates (m) Cr1 - Linear resistance coefficient (kg/[m.sup.3]s) Cr2 - Quadratic resistance coefficient (kg/[m.sup.4]) Greek Symbols [rho] - Fluid density (Kg/m3) [beta] - Porosity % [gamma] - Kinematic viscosity ([m.sup.2]/s) [epsilon] - Rate of dissipation of turbulence energy Appendix 1
where k is the turbulence kinetic energy, [epsilon] is the dissipation rate of turbulence energy, and [C.sub.[mu]] = 0.09 is an empirical constant.
The flow description is then realized within the average momentum (Reynolds) equation with the symmetric turbulent stress tensor [[sigma].sub.ij] = -[rho]<[v'.sub.j][v'.sub.i]> ([rho] is the medium density, [v'.sub.i] and [v'.sub.j] are components of v', the Latin indices i, j obtain the values 1, 2, and 3) and the equation for the turbulence energy K = 1/2 <[v'.sup.2]>.