On the behaviour of solid particles in a horizontal boundary layer with turbulence and saltation effects

1997 ◽  
Vol 23 (6) ◽  
pp. 463-471 ◽  
Author(s):  
A. Tanière ◽  
B. Oesterlé ◽  
J. C. Monnier
2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Sadia Siddiqa ◽  
Naheed Begum ◽  
M. A. Hossain ◽  
Rama Subba Reddy Gorla

This article is concerned with the class of solutions of gas boundary layer containing uniform, spherical solid particles over the surface of rotating axisymmetric round-nosed body. By using the method of transformed coordinates, the boundary layer equations for two-phase flow are mapped into a regular and stationary computational domain and then solved numerically by using implicit finite difference method. In this study, a rotating hemisphere is used as a particular example to elucidate the heat transfer mechanism near the surface of round-nosed bodies. We will investigate whether the presence of dust particles in carrier fluid disturbs the flow characteristics associated with rotating hemisphere or not. A comprehensive parametric analysis is presented to show the influence of the particle loading, the buoyancy ratio parameter, and the surface of rotating hemisphere on the numerical findings. In the absence of dust particles, the results are graphically compared with existing data in the open literature, and an excellent agreement has been found. It is noted that the concentration of dust particles’ parameter, Dρ, strongly influences the heat transport rate near the leading edge.


2006 ◽  
Vol 121 (2) ◽  
pp. 283-311 ◽  
Author(s):  
Ivana Vinkovic ◽  
Cesar Aguirre ◽  
Michel Ayrault ◽  
Serge Simoëns

2009 ◽  
Vol 47 (6) ◽  
pp. 892-901 ◽  
Author(s):  
A. I. Kartushinsky ◽  
I. A. Krupensky ◽  
S. V. Tisler ◽  
M. T. Hussainov ◽  
I. N. Shcheglov

2010 ◽  
Vol 652 ◽  
pp. 299-331
Author(s):  
P. G. DANIELS

This paper describes the boundary-layer structure of the steady flow of an infinite Prandtl number fluid in a two-dimensional rectangular cavity driven by differential heating of the upper surface. The lower surface and sidewalls of the cavity are thermally insulated and the upper surface is assumed to be either shear-free or rigid. In the limit of large Rayleigh number (R → ∞), the solution involves a horizontal boundary layer at the upper surface of depth of order R−1/5 where the main variation in the temperature field occurs. For a monotonic temperature distribution at the upper surface, fluid is driven to the colder end of the cavity where it descends within a narrow convection-dominated vertical layer before returning to the horizontal layer. A numerical solution of the horizontal boundary-layer problem is found for the case of a linear temperature distribution at the upper surface. At greater depths, of order R−2/15 for a shear-free surface and order R−9/65 for a rigid upper surface, a descending plume near the cold sidewall, together with a vertically stratified interior flow, allow the temperature to attain an approximately constant value throughout the remainder of the cavity. For a shear-free upper surface, this constant temperature is predicted to be of order R−1/15 higher than the minimum temperature of the upper surface, whereas for a rigid upper surface it is predicted to be of order R−2/65 higher.


2021 ◽  
Author(s):  
A.V. Dergunov ◽  
O.E. Yakubailik

The paper analyzes the meteorological conditions in the city of Krasnoyarsk in the period from January 1, 2019, to December 31, 2020. The relationship between temperature inversions in the surface layer of the atmosphere and air pollution by suspended solid particles PM25 is investigated. The paper uses a set of meteorological data of the NCEP GFS weather forecast model on the air temperature on three isobaric surfaces of 1000, 925, and 850 Mb; on wind gusts and the height of the atmospheric boundary layer. Data on PM25 solid particle concentrations and wind speed are provided by the air monitoring system of the KSC SB RAS. The relationship between the presence of temperature inversions in the lower layer of the atmosphere and periods of significant air pollution is shown, as well as the dependence of changes in wind speed and the height of the boundary layer of the atmosphere with changes in the average daily PM25 concentration. The results of the data analysis allow us to conclude that there is a high degree of correlation between these parameters. The possibility of using the meteorological data of the NCEP GFS model to study the surface layer of the atmosphere and the periods of its pollution, predicting the deterioration of the environmental situation in Krasnoyarsk, is demonstrated.


Sign in / Sign up

Export Citation Format

Share Document