Model comparison of two different non-hydrostatic formulations for the Navier-Stokes equations simulating wind flow in complex terrain

2017 ◽  
Vol 169 ◽  
pp. 290-307 ◽  
Author(s):  
Hermann Knaus ◽  
Alexander Rautenberg ◽  
Jens Bange
Keyword(s):  
Complex Terrain ◽  
Model Comparison ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Wind Flow ◽  
Navier Stokes Equations

Effect of the Separating Distance of Twin Buildings on the Generated Flow Structure

2010 ◽  
Vol 297-301 ◽  
pp. 924-929
Author(s):  
Inès Bhouri Baouab ◽  
Nejla Mahjoub Said ◽  
Hatem Mhiri ◽  
Georges Le Palec ◽  
Philippe Bournot
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Wind Flow ◽  
Turbulent Model ◽  
Navier Stokes Equations ◽  
Twin Buildings ◽  
Volume Method ◽  
Numerical Examination

The present work consists in a numerical examination of the dispersion of pollutants discharged from a bent chimney and crossing twin similar cubic obstacles placed in the lee side of the source. The resulting flow is assumed to be steady, three-dimensional and turbulent. Its modelling is based upon the resolution of the Navier Stokes equations by means of the finite volume method together with the RSM (Reynolds Stress Model) turbulent model. This examination aims essentially at detailing the wind flow perturbations, the recirculation and turbulence generated by the presence of the twin cubic obstacles placed tandem at different spacing distances (gaps): W = 4 h, W = 2 h and W = 1 h where W is the distance separating both buildings.

scholarly journals INVESTIGATION HYPERBOLIC PARABOLOID SHELL IN THE WIND TUNNEL AND COMPARISON WITH NUMERICAL SIMULATIONS

2018 ◽  
Vol 64 ◽  
Author(s):  
V.V. Stojanov ◽  
S. Jgalli
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Wind Flow ◽  
Hyperbolic Paraboloid ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Basic Model ◽  
The Impact

There are different ways to determine aerodynamic parameters, using analytical and experimental data for analyzing the behavior of structures when exposed to wind load. To date, the most developed is considered a numerical method for determining the characteristics of the above methods, based on the numerical solution of the Navier-Stokes equations. The accuracy of the results obtained using such a calculation method and obtaining the values of aerodynamic forces has increased due to the revision of mathematical models and the development of software complexes for the discretization of object bodies. This article gives an analytical overview of the results of research in the field of study the impact of wind loads on hypar (shell square in plan with the form of a hyperbolic paraboloid). The features of the investigated forms a discretization surface depending on pressure coefficients obtained in foreign literatures. Particular attention is paid to the numerical determination of aerodynamic coefficients on the surfaces of a hyperbolic paraboloid. The results were discussed and the nature of the distribution of coefficients depending on the angle of attack of the wind. Achieved analytical comparison computer modeling turbulent wind flows, based on solving the Reynolds equations arising from the use of averaging the Navier-Stokes equations. The basic model of turbulence such as: k-ε Standard Model; MMK; DBN; Shear-Stress Transport k-ω model; Transition k-kl-ω model. The possibility of choosing one or another model depending on the properties and characteristics of the wind flow is analyzed, for application in numerical simulation of wind flow around hyperbolic shells. The same was done, a comparative analysis of the results of physical testing in a wind tunnel with a numerical simulation in Ansys Fluent.

Numerical Site Calibration Over Complex Terrain

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Philippe Brodeur ◽  
Christian Masson
Keyword(s):  
Experimental Data ◽  
Numerical Method ◽  
Complex Terrain ◽  
Stokes Equations ◽  
Similarity Theory ◽  
Data Uncertainty ◽  
Navier Stokes ◽  
Special Treatment ◽  
Navier Stokes Equations ◽  
Roughness Lengths

This paper presents the development and assessment of a numerical method for simulated site calibration. The wind flow over complex terrain is predicted with a small length scale resolution. The flow field is resolved with the Reynolds averaged Navier–Stokes equations, complemented by the k‐ϵ turbulence model, with special treatment of the ground boundary to account for very large roughness lengths such as forest. The computational model is solved using FLUENT. A complex site, Riviere au Renard, located in Gaspesie, QC, Canada, has been selected and data have been collected from five met masts installed on this site. An experimental data analysis has been undertaken with emphasis on uncertainty evaluation. Three sets of results are presented. First, the numerical method is validated over flat terrain by comparing the simulation results with Monin–Obukhov similarity theory. Second, the assessment of the numerical method over complex terrain is done by comparing the wind velocity profiles at three of the met masts for three different wind orientations. Finally, traditional and numerical site calibrations for Riviere au Renard are presented for two wind directions. The numerical results are within the experimental data uncertainty.

scholarly journals Coordinates over Complex Terrain in Atmospheric Model

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Wen-yih Sun
Keyword(s):  
Complex Terrain ◽  
Stokes Equations ◽  
Atmospheric Model ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Vertical Coordinate ◽  
Curvilinear Coordinate ◽  
Terrain Following ◽  
Cartesian Coordinate ◽  
Energy And Momentum

In the terrain following coordinate, Gal-Chen and Somerville (1975) and other proposed a vertical coordinate  z*=(z-zb)/(zt-zb) and constant spatial intervals of dx* and  dy*along the other directions.  Because the variation of  and  was ignored, their coordinate does not really follow the terrain.  It fails to reproduce the divergence and curl over a complex terrain.  Aligning the coordinate with real terrain, the divergence and curl we obtained from the curvilinear coordinate are consistent with the Cartesian coordinate.  With a modification, the simulated total mass, energy, and momentum from the Navier-Stokes equations are conserved and in agreement with those calculated from Cartesian coordinate.

scholarly journals Stably stratified canopy flow in complex terrain

2014 ◽  
Vol 14 (21) ◽  
pp. 28483-28522
Author(s):  
X. Xu ◽  
C. Yi ◽  
E. Kutter
Keyword(s):  
Complex Terrain ◽  
Stokes Equations ◽  
Ground Surface ◽  
Strong Stability ◽  
Constant Heat Flux ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Canopy Layer ◽  
Canopy Flow ◽  
Navier Stokes Equations

Abstract. The characteristics of stably stratified canopy flows in complex terrain are investigated by employing the Renormalized Group (RNG) k-ε turbulence model. In this two-dimensional simulation, we imposed persistent constant heat flux at ground surface and linearly increasing cooling rate in the upper canopy layer, vertically varying dissipative force from canopy drag elements, buoyancy forcing induced from thermal stratification and the hill terrain. These strong boundary effects keep nonlinearity in the two-dimensional Navier–Stokes equations high enough to generate turbulent behavior. The fundamental characteristics of nighttime canopy flow over complex terrain measured by a few multi-tower advection experiments can be produced by this numerical simulation, such as: (1) unstable layer in the canopy, (2) super-stable layer associated with flow decoupling in deep canopy and near the top of canopy, (3) upward momentum transfer in canopy, and (4) large buoyancy suppression and weak shear production in strong stability.

scholarly journals A Numerical Study of Wind Flow Over a Coal Storage Shelter

10.14311/1692 ◽  
2012 ◽  
Vol 52 (6) ◽  
Author(s):  
Tomáš Bodnár ◽  
Ludek Beneš ◽  
Luboš Pirkl ◽  
Eva Gulíková
Keyword(s):  
Flow Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Wind Flow ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Structured Grid ◽  
Impermeable Wall ◽  
Volume Method

This paper presents some of the main numerical results obtained while simulating the wind flow over a shelter covering a coal storage. The aim of this numerical study was to evaluate the change in flow patterns caused by adding an impermeable wall to the originally open shelter. The numerical simulations of selected two-dimensional cases were performed using an open-source CFD code. The flow model is based on Reynolds-Averaged Navier-Stokes Equations solved using a finite-volume method on a structured grid. The turbulence is parametrized using the standard k − ε model. Two shelter wall configuration variants are evaluated, and are compared with the original open shelter setup.

Wind-Induced Response of ADSS during the Passage of High-Speed Train

2014 ◽  
Vol 590 ◽  
pp. 69-73
Author(s):  
Yu Wang ◽  
Qiang Gao ◽  
Hai Lin Wang
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Induced Response ◽  
Wind Flow ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
High Speed Trains

In this paper, the wind-induced response of the ADSS is analyzed when the high-speed trains pass by. The wind flow field of the high-speed train is simulated based on the three-dimensional Reynolds-averaged Navier–Stokes equations, combined with the k-ε turbulence model. The result is shown that the wind load acting on the ADSS is quite low and the stress of the line clamp increases a little.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

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