Author:
BRIASSULIS G.,AGUI J. H.,ANDREOPOULOS Y.
Abstract
A decaying compressible nearly homogeneous and nearly isotropic grid-generated
turbulent flow has been set up in a large scale shock tube research facility. Experiments
have been performed using instrumentation with spatial resolution of the order
of 7 to 26 Kolmogorov viscous length scales. A variety of turbulence-generating grids
provided a wide range of turbulence scales with bulk flow Mach numbers ranging
from 0.3 to 0.6 and turbulent Reynolds numbers up to 700. The decay of Mach
number fluctuations was found to follow a power law similar to that describing the
decay of incompressible isotropic turbulence. It was also found that the decay coefficient
and the decay exponent decrease with increasing Mach number while the virtual
origin increases with increasing Mach number. A possible mechanism responsible
for these effects appears to be the inherently low growth rate of compressible shear
layers emanating from the cylindrical rods of the grid. Measurements of the time-dependent,
three dimensional vorticity vectors were attempted for the first time with
a 12-wire miniature probe. This also allowed estimates of dilatation, compressible
dissipation and dilatational stretching to be obtained. It was found that the fluctuations
of these quantities increase with increasing mean Mach number of the flow. The
time-dependent signals of enstrophy, vortex stretching/tilting vector and dilatational
stretching vector were found to exhibit a rather strong intermittent behaviour which
is characterized by high-amplitude bursts with values up to 8 times their r.m.s. within
periods of less violent and longer lived events. Several of these bursts are evident
in all the signals, suggesting the existence of a dynamical flow phenomenon as a
common cause.
Publisher
Cambridge University Press (CUP)
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Cited by
44 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献