Linear Processes in Stratified Turbulence with Rotation or Mean Shear
Linear processes of the unsteady turbulence in stratified flow with system rotation or mean shear are analysed by the rapid distortion theory (RDT). In stratified rotating turbulence, the ratio of Coriolis parameter f to Brunt-Väisälä frequency N, i.e. f/N, determines the steady components of energy and the phase of energy/flux oscillation. On the other hand, unsteady aspects are dominated by stratification, and the energy/flux oscillates at frequency ~ 2N as in the flow with only stratification. For stratified shear flow, the energy or the flux again oscillates at frequency 2N, although the shear distorts the energy spectra so that they are more localized to smaller stream-wise wavenumbers (k 1 → 0). The results show that neither rotation nor mean shear affects the wave number components which dominate the buoyancy oscillation of the energy and the flux.
KeywordsLarge Eddy Simulation Direct Numerical Simulation Linear Process Direct Numerical Simulation Data Applicability Condition
Unable to display preview. Download preview PDF.
- 5.Derbyshire, S. H. & Hunt, J. C. R. ’Structure of turbulence in stably stratified atmospheric boundary layers; Comparison of large eddy simulations and theoretical results’. In: Waves and Turbulence in Stably Stratified Flows, ed. by S. D. Mobbs and J. C. King, (Clarendon Press 1993) pp. 23–59Google Scholar
- 8.Hanazaki, H. ’On the transport mechanisms in stably stratified rotating turbulence’. In: Turbulence, Heat and Mass Transfer 3, ed. by Y. Nagano, K. Hanjalic & T. Tsuji, (Aichi Shuppan 2000) pp. 639–644Google Scholar
- 9.Hanazaki, H. Linear processes in stably and unstably stratified rotating turbulence. J. Fluid Mech. in press, (2002)Google Scholar
- 11.Hanazaki, H. & Hunt, J. C. R. ’Linear processes in unsteady stratified sheared turbulence’. In: IUTAM Symp. on Geometry and Statistics of Turbulence, ed. by T. Kambe, T. Nakano & T. Miyauchi, (Kluwer 2001) pp. 291–296Google Scholar
- 12.Hanazaki, H. & Hunt, J. C. R. Structures of unsteady stably stratified turbulence with mean shear. submitted to J. Fluid Mech. (2002)Google Scholar
- 14.Hunt, J. C. R., Stretch, D. D. & Britter, R. E. ’Length scales in stably stratified turbulent flows and their use in turbulence models’. In: Stably Stratified Flow and Dense Gas Dispersion, ed. by J. S. Puttock, (Clarendon Press 1988), pp. 285–321Google Scholar
- 33.Stretch, D. D. The dispersion of slightly dense contaminations in a turbulent boundary layer. Ph.D. Thesis, Dept. of Engineering, University of Cambridge (1986)Google Scholar
- 35.Tsujimura, S., Iida, O. & Nagano, Y. ’Effects of rotation on unstably stratified turbulence’. In: Proc. Int. Conf. on Turbulent Heat Transfer 2, Manchester, U. K. vol. 1, 5–58 – 5–71 (1998)Google Scholar