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https://hdl.handle.net/11681/44766| Title: | A tutorial on the rapid distortion theory model for unidirectional, plane shearing of homogeneous turbulence |
| Authors: | Hart, Carl R. Lyons, Gregory W. |
| Keywords: | Winds Atmospheric turbulence Sound--Propagation Sound--Transmission Noise Acoustical engineering |
| Publisher: | Engineer Research and Development Center (U.S.) |
| Series/Report no.: | Technical Report (Engineer Research and Development Center (U.S.)) ; no. ERDC SR-22-2 |
| Abstract: | The theory of near-surface atmospheric wind noise is largely predicated on assuming turbulence is homogeneous and isotropic. For high turbulent wavenumbers, this is a fairly reasonable approximation, though it can introduce non-negligible errors in shear flows. Recent near-surface measurements of atmospheric turbulence suggest that anisotropic turbulence can be adequately modeled by rapid-distortion theory (RDT), which can serve as a natural extension of wind noise theory. Here, a solution for the RDT equations of unidirectional plane shearing of homogeneous turbulence is reproduced. It is assumed that the time-varying velocity spectral tensor can be made stationary by substituting an eddy-lifetime parameter in place of time. General and particular RDT evolution equations for stochastic increments are derived in detail. Analytical solutions for the RDT evolution equation, with and without an effective eddy viscosity, are given. An alternative expression for the eddy-lifetime parameter is shown. The turbulence kinetic energy budget is examined for RDT. Predictions by RDT are shown for velocity (co)variances, one-dimensional streamwise spectra, length scales, and the second invariant of the anisotropy tensor of the moments of velocity. The RDT prediction of the second invariant for the velocity anisotropy tensor is shown to agree better with direct numerical simulations than previously reported. |
| Description: | Special Report |
| Gov't Doc #: | ERDC SR-22-2 |
| Rights: | Approved for Public Release; Distribution is Unlimited |
| URI: | https://hdl.handle.net/11681/44766 http://dx.doi.org/10.21079/11681/44766 |
| Appears in Collections: | Special Report |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ERDC SR-22-2.pdf | 1 MB | Adobe PDF |  View/Open |