Rui-Rong Chen

EFFECTS OF ROTATION ON CONVECTIVE TURBULENCE

Laboratory experiments were carried out to investigate the effects of rotation on turbulent convection. The experimental facility was a bottom-heated, water-filled, cubical tank mounted on a turntable. The investigations were performed over a wide range of bottom buoyancy fluxes q 0 and rotation rates Ω, including Ω = 0; q 0 and Ω were held constant during each experiment. The depth of the water column H was fixed for the entire experimental programme. For the non-rotating experiments, the r.m.s. velocity fluctuations were found to scale well with the convective velocity

Synoptic classification and physical model experiments to guide field studies in complex terrain

w_* = (q_0 H)^{\frac{1}{3}}

Turbulent thermal convection in rotating and stratified fluids

, while the mean and r.m.s. fluctuations of buoyancy were found to scale with q 0 / w * . The spectra of temperature fluctuations were measured and were used to assess the applicability of two types of scaling, one of which is advanced in the present study. For the rotating experiments, the convective-layer growth is affected by the rotation at a height h c ≈ 4.5( q 0 Ω −3 ) ½ . The r.m.s. horizontal velocity of the rotationally affected mixed layer is uniform throughout the mixed layer and is given by

Physical Model of Diurnal Heating in the Vicinity of a Two-Dimensional Ridge

(\overline{u^{\prime 2}})^{\frac{1}{2}}_{\rm r}\approx 1.7(q_0\Omega^{-1})^{\frac{1}{2}}

Laboratory Simulation of Tidal Rectification over Seamounts: Homogeneous Model

. The time growth law of the mixed-layer thickness h r , when h r > h c , is given by h r ≈ 0.7( q 0 Ω −3 ) ½ Ω t , where t is the time. The rotational effects become important when the Rossby number is given by

Laboratory Simulation of Mountain Effects on Large-Scale Atmospheric Motion Systems. The Rocky Mountains

Ro = (\overline{u^{\prime 2}})^{\frac{1}{2}}_{\rm r}/\omega l_{\rm r}\approx 1.5

On the formation and shedding of vortices from side-wall mounted obstacles in rotating systems

, where the integral lengthscale is estimated as l r ≈ 0.25 h c . The mean buoyancy gradient in the mixed layer was found to be much higher than in the corresponding non-rotating case, and the r.m.s. fluctuations and mean buoyancies were found to scale satisfactorily with ( q 0 Ω) ½ . A spectral form for the temperature fluctuations in rotating convection is also proposed and is compared to the experimental results.

Physical model of bathymetric effects on the Antarctic circumpolar current

Abstract Synoptic classification is used to identify meteorological conditions characteristic of high-pollution periods at Nogales, Arizona. Low surface winds determined by local surface cooling at night with little vertical mixing were found to be most important. This condition was simulated in a 0.79-m-square box filled with water with the lower surface made to model a 12-km-square region of the surface topography of the United States-Mexico border at Nogales. The aluminum base was cooled to induce the downslope flows. Photographs of dye initially placed on the surface at many locations were used to obtain a set of surface velocities that formed the input to the Diagnostic Wind Model (DWM). The DWM provided hourly velocity data with grids of 500- and 250-m spacings. The similarity arguments used to analyze the relationship of the physical model to the atmosphere are discussed. Although the magnitude of the wind vectors in the physical model cannot be matched to the atmosphere, the directions can be used...

Laboratory Simulation of Atmospheric Motions in the Vicinity of Antarctica

Abstract During the past two decades, numerous laboratory experiments have been performed to understand the influence of rotation and stratification on turbulence induced by thermal convection. A brief overview of these studies and their geophysical implications are presented and some potential future research areas are identified. Some preliminary observations of laboratory studies in progress on entrainment and mixing in rotating and stratified fluids are also outlined.

Formation of isolated vortices in a rotating convecting fluid

Abstract Laboratory experiments were conducted to simulate the diurnal heating-cooling cycle in the vicinity of a ridge of constant cross section. In the model the fluid is a water solution stratified with salt to simulate the background stratification of the atmosphere. The flow is driven by recirculating water of a controlled temperature beneath the model; the model surface temperature is thus varied in a specified way to simulate the surface heating by solar insolation during the daytime hours and surface cooling by radiation during the nighttime. The pertinent similarity parameters are shown to be Gc, for daytime convective flow and Gd for nocturnal flow; here Gc = Hb/Hc, Gd = Hb/Hd, where Hb, is the mountain height, Hc the neutral buoyancy height of free convection. and Hd the characteristic thickness of the nighttime drainage flow. The model demonstrates some of the principal features of thermally driven mountain circulations, including daytime upslope winds and nocturnal downslope drainage flows. T...