We present a low-Mach number fix for Roe's approximate Riemann solver (LMRoe).
Simulations of turbulent channel flow for Reτ= 180 show that, with the 'low-Mach-fix for Roe' (LMRoe) proposed by Rieper [J. Comput. Phys. 230 (2011) 5263 5287], the Roe dissipation term potentially equates the simulation to an implicit large eddy simulation (ILES) at low Mach number.
Could Mach make it in Vente-Privee pink? he asked.
The Lighthill's equation for pressure fluctuations is derived in a frame of reference fix with respect to the plate, at low Mach numbers, and transformed into the convected frame moving with the flow.
In the close proximity of the saturation curve, near the critical point, molecularly complex organic fluids for ORC applications may exhibit a number of non-ideal gasdynamic effects, including a remarkable dependency of the shock properties on the upstream thermodynamic state of the fluid, at a fixed upstream Mach number.
For a fixed fan-stream Mach number, it is observed that the shock-associated noise often drops suddenly to a minimum as the reservoir pressure of the primary jet increases.
Here we keep the Froude number Fr fixed and consider only the Mach number to be small.
An incompressible limit does exist if the non-hydrodynamic relaxation times are not fixed, but scaled by the Mach number in the same way as the hydrodynamic relaxation time that determines the viscosity.
A new aspect, presented in this paper, is the dependence on the cell geometry: applied on a triangular grid, the accuracy problem disappears, i.e. flows of arbitrarily small Mach numbers can be simulated on a fixed mesh.
And in certain models of the theory, such as the Big Bang cosmological models, some authors have claimed that the local standards of inertial motion — the local 'gravitational field' of Einstein's equivalence principle — are entirely fixed by the matter distribution throughout space and time, just as Mach-heavy requires (see, for example, Wheeler and Cuifollini 1995).
The upper filter was fixed to the actuator controlled electronically by the mechanical testing machine (Mach-1, Biomomentum, Montreal, QC, Canada).
