Secondary Currents in Wall TurbulenceAIP Publishing - Tập 10 Số 9 - Trang S122-S125 - 1967
J. O. Hinze
Considering the region not too close to the wall, application of the usual boundary-layer approximations to the balance equation for the turbulence kinetic energy leads to the following rule: When in a localized region the production is much greater (smaller) than the dissipation, there must be a secondary current that transports turbulence-poor fluid into (outwards) this region and turbul...... hiện toàn bộ
The electron-acoustic modeAIP Publishing - Tập 28 Số 8 - Trang 2439-2441 - 1985
S. Peter Gary, R. L. Tokar
This paper examines electrostatic modes in an unmagnetized, homogeneous, Vlasov plasma with three Maxwellian components: ions, hot electrons, and cool electrons. In such a plasma, the electron-acoustic mode with frequencies between the ion and electron plasma frequencies may propagate with light damping. The conditions that allow propagation of this mode, which is distinct from the well-kn...... hiện toàn bộ
Decay of Isotropic Turbulence Generated by a Mechanically Agitated GridAIP Publishing - Tập 15 Số 8 - Trang 1363-1369 - 1972
S. C. Ling, Chaoyi Wan
Experimental study of weak isotropic turbulence, created by a mechanically agitated grid, has indicated that in the absence of large linear-momentum wakes the energy of turbulence relaxes very quickly into a stable self-preserving structure, which, depending on the initial Reynolds number of turbulence, decays at different constant inverse powers of time. Both the longitudinal correlation ...... hiện toàn bộ
Small Reynolds number nearly isotropic turbulence in a straight duct and a contractionAIP Publishing - Tập 21 Số 12 - Trang 2129-2140 - 1978
J. Bennett, S. Corrsin
Measurements have been made of nearly isotropic, low Reynolds number, grid-generated turbulence. The decay results agree with the predictions for ’’final period’’ isotropic turbulence decay (in time) by the linear approximation of von Kármán and Howarth, and Batchelor and Townsend. This agreement occurs in spite of the fact that at the smallest turbulence Reynolds number attained, Rλ≈4, th...... hiện toàn bộ
Effect of Grid Geometry on Turbulence DecayAIP Publishing - Tập 10 Số 6 - Trang 1216-1224 - 1967
Mahinder S. Uberoi, Stanley Wallis
Longitudinal and lateral turbulence intensities u2¯ and v2¯ are measured behind homogeneous grids of various geometries. For all grids used, the ratio u2¯/v2¯ is essentially constant during decay and lies between 1.2 and 1.35, depending on the grid geometry. The turbulence intensity u2¯∼t−n where n is constant during decay but depends on the grid geometry and varies from 1.22 to 1.48. This...... hiện toàn bộ
An examination of hot-wire length correctionsAIP Publishing - Tập 26 Số 7 - Trang 1751-1754 - 1983
R. W. Derksen, R. S. Azad
A comprehensive experimental examination is presented of the effect of hot-wire length for a single-wire probe. Specially constructed hot wires, with 2.5 μm and 5.0 μm nominal diameters and lengths from 0.3 mm to 2.8 mm, were used to measure the one-dimensional spectrum of the streamwise fluctuating velocity component u as well as the skewness and flatness of both u and du/dt. All measurem...... hiện toàn bộ
Spectra of Grid TurbulenceAIP Publishing - Tập 12 Số 7 - Trang 1355-1358 - 1969
Mahinder S. Uberoi, Stanley Wallis
Energy spectra of the longitudinal and lateral turbulent velocities are measured behind grids of different geometries; the isotropic relation is not satisfied. Energy-dissipating eddies are more nearly isotropic than energy-containing eddies. Spectra of the energy-containing eddies and their deviation from isotropy depend on the grid geometry. Various microscales are measured to determine ...... hiện toàn bộ
Experiments on turbulence behind a grid with jet injection in downstream and upstream directionAIP Publishing - Tập 18 Số 4 - Trang 411-414 - 1975
Y. Tassa, Y. Kamotani
Turbulence behind a biplanar grid with jets of air injected at the grid surface either in the upstream or the downstream direction was found to be nearly isotropic for x/M ≳ 20. Turbulence level increases with the injection rate for both upstream and downstream injection. The shape of the energy spectrum functions and microscales do not vary with the injection rate. The microscales for ups...... hiện toàn bộ
Internal Wave Wakes of a Body Moving in a Stratified FluidAIP Publishing - Tập 13 Số 6 - Trang 1425-1431 - 1970
Joseph B. Keller, Walter Munk
Equations are derived for the wake produced by a source of waves moving in any dispersive homogeneous anisotropic medium. The behavior of the wake far from the source and near the source path are examined in detail. Then, internal waves in a stratified fluid with a thermocline of finite thickness are considered. The dispersion equations for all the propagating modes, of which there are inf...... hiện toàn bộ