Abstract Observations of the real‐time state atmosphere are required in order to initialize numerical weather prediction (NWP) models. As NWP resolution improves, more observations needed, better capture regional variations atmospheric conditions. In particular, surface necessary reflect conditions experienced on surface. One proposed opportunity increase number available for assimilation into is crowdsource data from home stations. This study investigates outdoor air temperature...

The effect of a radial temperature gradient on the hydrodynamic stability in annular gap formed by two, vertical, concentric cylinders, inner being rotatable and outer both stationary isothermally heated, was studied for cases zero imposed axial fluid flow gap. For flow, it found that destabilizes while not affecting form secondary viz. classic Taylor vortex. point neutral modified only when natural convection strong enough to affect parabolic velocity profile associated with flow; extent...

Abstract The results of a finite difference analysis are presented for the problem incompressible laminar flow heat transfer in concentric annuli with simultaneously developing hydrodynamic and thermal boundary layers, conditions one wall being isothermal other adiabatic. This corresponds to fundamental solution third kind according four solutions classified by Reynolds, Lundberg McCuen 1 . Firstly, entry length problem, based on layer simplifications Navier–Stokes equations, was solved...

The boundary layer simplification of the Navier-Stokes equations for hydrodynamically developing laminar flow with constant physical properties in entrance region concentric annuli rotating inner walls have been numerically solved using a simple linearized finite-difference scheme. Additional results to those existing literature by Martin and Payne [1–2] will be presented here. An advantage analysis used this paper is that it does not solve stream function vorticity, but predicts development...

A theoretical analysis of the performance a cooling and dehumidifying vertical rectangular fin has been carried out. Conventional theory based on assumption uniform known sensible heat-transfer coefficient was extended by incorporating condensate thermal resistance thickness into for gravity-controlled flow during dehumidification. The layer equations were solved numerically evaluated both insulated uninsulated tip boundary conditions, assuming Biot number at tip. Numerical results are...

An experimental study has been carried out to investigate the performance of a vertical rectangular fin finite thickness and moderate size when dehumidification occurs in turbulent flow. Tests were conducted for various free-stream velocities relative humidities blunt leading edged under both dry wet conditions. Further tests also devised an attached elliptical edge. Lower surface temperatures recorded edge due absence flow separation reattachment. During tests, water droplets sizes formed...

Technical Briefs Laminar Heat Transfer in the Entrance Region of Concentric Annuli With Rotating Inner Walls J. E. R. Coney, Coney Mechanical Engineering Department, University Leeds, England Search for other works by this author on: This Site PubMed Google Scholar M. A. I. El-Shaarawi Author and Article Information Transfer. Nov 1974, 96(4): 560-562 (3 pages) https://doi.org/10.1115/1.3450252 Published Online: November 1, 1974 history Received: March 14, August 11, 2010

The results of a shear stress investigation for combined axial and rotational flow, under conditions both laminar flow plus Taylor vortices, are presented. These show that two distinct régimes dependency exist. In the primary régime, is constant depends only on imposed being either (Poiseuille Couette flows) or with but effect vortices negligible. secondary shown to depend Ta 0.735 , irrespective flow. At low rates, tertiary régime was observed, no satisfactory explanation can be found this...

The hydrodynamic stability of the flow in an annular gap, formed by a stationary outer cylinder and rotatable inner cylinder, through which axial air can be imposed, is studied experimentally. Two annulus radius ratios 0.8 0.955 are considered, representing wide- narrow-gap conditions, respectively. It shown that, when large, pressure gradient superimposed on tangential induced rotation characteristics at criticality change significantly from those zero low flows, length width resultant...

Results are presented of an investigation into a developing, combined axial and rotational flow in annular gap formed by stationary outer cylinder rotatable inner for annulus radius ratio 0–8 Reynolds number 1200. These results show that, the Taylor vortex régime, development length decreases with parameter Re 2 /Ta that greatest gap, given number, occurs when is near to its critical value. Consideration isothermal heat transfer through wall suggests flow, Nusselt rises high value before...

This experimental investigation is devoted to the study of combined axial and rotational flow in a concentric annular gap, radius ratio 0.8, formed by stationary outer rotatable inner cylinder. Taylor numbers varying from critical an order 10 6 will be considered. The divided into three parts, illustrating different aspects spiral vortex flow. Firstly, evolution with increasing number at constant Reynolds studied analysis spectrum signal hot-wire anemometer. Secondly, wave length drift...

Trapped lee waves, and resultant turbulent rotors downstream, present a hazard for aviation land‐based transport. Though high‐resolution numerical weather prediction models can represent such phenomena, there is currently no simple reliable automated method detecting the extent characteristics of these waves in model output. Spectral transform methods have traditionally been used to detect characterise regions wave activity observational data; however, be slow their limitations....

The influence of side leakage on the onset Taylor vortices in high-speed journal bearings is studied by observing effects varying eccentricity of, and axial flow through, an annulus. apparatus permits both sharp smooth entries to Flow visualization achieved means aluminium paint pigment suspended test fluid. It shown that have a marked effect critical number. Evidence presented for co-existence two systems within