| Popis: |
This paper reports on the extension of second‐order models for unforced isotropic turbulence to the compressible regime. The equations contain two principal compressibility terms: the dilatation dissipation and the pressure–dilatation correlation. The dilatation dissipation has been modeled in accordance with the shocklet dissipation theory of Zeman [Phys. Fluids A 2, 178 (1990)]; the pressure–dilatation term has been identified with the rate of change of compressible potential energy represented by the pressure fluctuation variance ∼(p2). The rate of change of ∼(p2) is assumed to be governed by a nonlinear relaxation mechanism that drives ∼(p2) to an equipartition value. By comparison with direct numerical simulations of 2‐D and 3‐D turbulence, it is shown that the extended turbulence energy equations are capable of simulating the compressibility effects associated with rms Mach number and the (initial) pressure fluctuations. |
