Stochastic Estimation of Cavity Flowfield

Linear stochastic estimation and quadratic stochastic estimation techniques were applied to estimate the entire velocity flow-field of an open cavity with a length to depth ratio of 2. The estimations were done through the use of instantaneous velocity magnitude as estimators. These measurements were obtained by Particle Image Velocimetry. The predicted flow was compared against the original flow-field in terms of the Reynolds stresses and turbulent kinetic energy. Quadratic stochastic estimation proved to be more superior than linear stochastic estimation in resolving the shear layer flow. When the velocity fluctuations were scaled up in the quadratic estimate, both the time-averaged quantities and the instantaneous cavity flow can be predicted to a rather accurate extent.

Authors:

• Yin Yin Pey
• Leok Poh Chua
• Wei Long Siauw

Keywords:

• Open cavity
• Particle Image Velocimetry
• Stochastic estimation
• Turbulent kinetic energy.

References:

[1] R.J. Adrian, "On the Role of Conditional Averages in Turbulence
Theory," in Proceeding of the 4th Biennial Symposium on Turbulence in
Liquids. 1975: Univ. of Missouri, Rolla, MO.
[2] Y.G. Guezennec, "Stochastic estimation of coherent structures in
turbulent boundary layers," Physics of Fluids A (Fluid Dynamics), 1989.
1(6): pp. 1054-60.
[3] D.R. Cole, M.N. Glauser, and Y.G. Guezennec, "An application of the
stochastic estimation to the jet mixing layer," Physics of Fluids A (Fluid
Dynamics), 1992. 4(1): pp. 192-4.
[4] D.R. Cole, and M.N. Glauser, "Applications of stochastic estimation in
the axisymmetric sudden expansion," Physics of Fluids, 1998. 10(11):
pp. 2941-9.
[5] S. Stokes, and M. Glauser, "Multi-point measurement techniques used in
the study of separated flows," in 30th AIAA Fluid Dynamics Conference,
AIAA, Editor. 1999: Reno, NV.
[6] T.C. Tung, and R.J. Adrian, "Higher-order estimates of conditional
eddies in isotropic turbulence," Physics of Fluids, 1980. 23(7): pp. 1469-
70.
[7] A.M., Naguib, C.E. Wark, and O. Juckenhofel, "Stochastic estimation
and flow sources associated with surface pressure events in a turbulent
boundary layer," Physics of Fluids, 2001. 13(9): pp. 2611-26.
[8] N.E. Murray, and L.S. Ukeiley, "Estimating the shear layer velocity
field above an open cavity from surface pressure measurements," in
32nd AIAA Fluid Dynamics Conference and Exhibit, June 24 2002- June
26 2002. St. Louis, Missouri: AIAA.
[9] N.E. Murray, and L.S. Ukeiley, "Low-dimensional estimation of cavity
flow dynamics," in 42nd AIAA Aerospace Sciences Meeting and Exhibit,
January 5, 2004 - January 8, 2004. Reno, NV, United states: American
Institute of Aeronautics and Astronautics Inc.
[10] J.A. Taylor, and M.N. Glauser, "Towards practical flow sensing and
control via POD and LSE based low-dimensional tools," Transactions of
the ASME. Journal of Fluids Engineering, 2004. 126(3): pp. 337-45.
[11] L.M. Hudy, A. Naguib, and W.M. Humphreys, "Stochastic estimation of
a separated-flow field using wall-pressure-array measurements," Physics
of Fluids, 2007. 19(2): pp. 24103-1.
[12] R.J. Adrian, "Conditional eddies in isotropic turbulence," Physics of
Fluids, 1979. 22(11): pp. 2065-70.