A Preliminary Numerical Study of Atmospheric Turbulent Flows in the Idealized Planetary Boundary Layer

1973 ◽  
Vol 30 (7) ◽  
pp. 1327-1339 ◽  
Author(s):  
C. C. Shir
Keyword(s):  
Boundary Layer ◽  
Turbulent Flows ◽  
Planetary Boundary Layer ◽  
Numerical Study

A Numerical Study of Laminar and Intermittently Turbulent Boundary Layer on an Oscillating Flat Plate Using Pseudo-Compressible RANS Model

2020 ◽  
Author(s):  
Shivank Srivastava ◽  
Brandon M. Taravella ◽  
Kazim M. Akyuzlu
Keyword(s):  
Boundary Layer ◽  
Turbulent Flow ◽  
Flat Plate ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Rans Model ◽  
Explicit Finite Difference ◽  
Turbulent Flow Conditions

Abstract A numerical study was conducted to study the unsteady characteristics of incompressible boundary layer flows over an oscillating flat plate under laminar and intermittently turbulent flow conditions using pseudo-compressible Reynolds Averaged Navier-Stokes (RANS) model. The numerical study is carried out using an in-house code and a commercial CFD package (Fluent). Two equation (k-ε) turbulence closure model, modified near the wall, is used along with RANS equations to simulate intermittently turbulent flows. Fully Explicit-Finite Difference technique (FEFD) is employed to solve the governing differential equations. For validation purposes, the velocity fields predicted by the in-house code and commercial CFD package are compared to the one given by analytical solution to Stokes’ second problem for an oscillating flat plate. Numerical experiments were conducted for unsteady cases for Stokes’ Reynolds number corresponding to laminar and intermittently turbulent flows, respectively. Time dependent velocity profiles, shear stress distribution, turbulence properties during the accelerating and decelerating stages of oscillations are predicted. The above predictions are then compared to ones predicted by commercial CFD code. The velocity magnitudes predicted by the in-house code and commercial CFD code are within acceptable range for laminar and intermittently turbulent flow conditions.

Numerical study of a mesoscale vortex in the planetary boundary layer of the meiyu front

2012 ◽  
Vol 26 (6) ◽  
pp. 788-802 ◽  
Author(s):  
Hangfeng Shen ◽  
Guoqing Zhai ◽  
Ye Zhu ◽  
Yaqin Xu
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Numerical Study ◽  
Mesoscale Vortex ◽  
Meiyu Front

scholarly journals Numerical Study of the Daytime Planetary Boundary Layer over an Idealized Urban Area: Influence of Surface Properties, Anthropogenic Heat Flux, and Geostrophic Wind Intensity

2016 ◽  
Vol 55 (4) ◽  
pp. 1021-1039 ◽  
Author(s):  
Serena Falasca ◽  
Franco Catalano ◽  
Monica Moroni
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Numerical Study ◽  
Geostrophic Wind ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Control Parameters ◽  
Reference Case ◽  
Anthropogenic Heat Flux ◽  
Wind Intensity

AbstractLarge-eddy simulations of an idealized diurnal urban heat island are performed using the Weather Research and Forecasting Model. The surface energy balance over an inhomogeneous terrain is solved considering the anthropogenic heat contribution and the differences of thermal and mechanical properties between urban and rural surfaces. Several cases are simulated together with a reference case, considering different values of the control parameters: albedo, thermal inertia, roughness length, anthropogenic heat emission, and geostrophic wind intensity. Spatial distributions of second-moment statistics, including the turbulent kinetic energy (TKE) budget, are analyzed to characterize the structure of the planetary boundary layer (PBL). The effect of each control parameter value on the turbulent properties of the PBL is investigated with respect to the reference case. For all of the analyzed cases, the primary source of TKE is the buoyancy in the lower half of the PBL, the shear in the upper half, and the turbulent transport term at the top. The vertical advection of TKE is significant in the upper half of the PBL. The control parameters significantly influence the shape of the profiles of the transport and shear terms in the TKE budget. Bulk properties of the PBL via proper scaling are compared with literature data. A log-linear relationship between the aspect ratio of the heat island and the Froude number is confirmed. For the first time, the effect of relevant surface control parameters and the geostrophic wind intensity on the bulk and turbulent properties of the PBL is systematically investigated at high resolution.

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