Combustion, propulsion, chemical and other industrial problems
How?
Create SHI – Stationary, (nearly) Homogeneous, and (nearly) Isotropic flow and mixing: closed vessels and/or propellers, HEV…
The ‘porcupine’: R. Betchov, 1957
‘
Synthetic jets’ in cubic chamber - W. Hwang and J.K. Eaton (E. Fluids, 2003)
Propellers - Birouk, Sahr and Gokalp (F. Turb. & Comb, 2003)
Synthetic jets - J.P. Marié
French Washing Machine
III. DESCRIPTION of the FLOW: fluctuating field; local approach;
3-rd order SF
2-nd order SF with the Kolmogorov constant Ck=2 ..
Normalized dissipation which L? Attention to initial conditions versus universality .. However, a reliable test
The most reliable test is the 1—point energy budget equation, when the pressure-related terms could be neglected (point II).
III. DESCRIPTION of the FLOW: fluctuating field; PIV for determining small scale properties
The other tests
2-rd order SF with the Kolmogorov constant
Normalized dissipation which L? Attention to initial conditions versus universality .. However, a reliable test
for
The most reliable test is the 1—point energy budget equation, when the pressure-related terms might be neglected (point II).
III. DESCRIPTION of the FLOW: fluctuating field; back to PIV for determining small scale properties
III. DESCRIPTION of the FLOW: fluctuating field; back to PIV for determining small scale properties
III. DESCRIPTION of the FLOW: fluctuating field; back to PIV for determining small scale properties
III. DESCRIPTION of the FLOW: fluctuating field; back to PIV for determining small scale properties
III. DESCRIPTION of the FLOW: fluctuating field; LDV for determining small scale properties
a) LDV in 1 point mean velocity, RMS, small-scales quantities (definitions, correlations, SF2, SF3, 1-point energy budget equation… ). Good to determine the RMS and to compare with the PIV results (15% difference).
Drawback: Taylor’s hypothesis is needed, in a flow where the turbulence intensity varies from 100% to infinity (stagnation points ..).
LDV in two points simultaneous measurements of one velocity component in 2 spatial points (separation parallel to the measured velocity direction)… many points.
Different methods: SF2, SF3, definition of
1-point energy budget equation (pressure … good for point II).
