نویسندگان
دانشگاه علم و صنعت ایران
چکیده
هدف از این مطالعه بررسی و تحلیل عددی مکانیزم‌های مؤثر بر میدان جریان و پراکندگی آلاینده‌ها پیرامون یک دره خیابانی ساده و طویل توسط رهیافت شبیه‌سازی گردابه‌های بزرگ با استفاده از چندین روش مختلف تولید آشفتگی ورودی است. به‌همین منظور، از چهار روش گردابه، نگاشتی، سنتزی و بدون آشفتگی ورودی به‌عنوان تولید کننده‌های آشفتگی ورودی در رهیافت شبیه‌سازی گردابه‌های بزرگ استفاده شده است. نتایج حاکی از آن است که تمامی روش‌ها قادر به پیش‌بینی دو ساختار مهم گردابه دره و گردابه گوشه هستند که تأثیر زیادی بر تهویه هوای داخل دره خیابانی می‌گذارند. مقادیر غلظت برروی دیوار بادپناه ساختمان اول حدود 4 برابر دیوار بادگیر ساختمان دوم به‌دست آمده است. از بین روشهای مختلف تولید آشفتگی ورودی، روش گردابه دقیق‌ترین روش و روش بدون آشفتگی ورودی، کم‌دقت‌ترین روش است.
کلیدواژه‌ها
عنوان مقاله [English]
Analysis of Various Inflow Turbulence Generation Methods in Large Eddy Simulation Approach for Prediction of Pollutant Dispersion around Model Buildings
نویسندگان [English]
- F. Bazdidi Tehrani
- D. Badaghi
- M. Kiamansori
- M. Jadidi
چکیده [English]
The purpose of the present study is to investigate and analyze numerically, the effective mechanisms on the flow field and pollutant dispersion around a simple and long street canyon by means of Large Eddy Simulation (LES) approach using various inflow turbulence generation methods. For this purpose, four methods i.e. vortex, mapping, synthetic and no-inlet perturbation methods are used as inflow turbulence generators in LES. Results suggest that all methods are capable of capturing the two important structures of canyon vortex and corner eddy, which have great influences on air ventilation inside the street canyon. The magnitudes of concentration on the leeward wall of the first building are approximately four times as much as those
of windward wall of the second building. Among the various inflow turbulence generation methods, the vortex method is the most precise method and no-inlet perturbation method is the least precise method.
کلیدواژه‌ها [English]
- Pollutant dispersion
- Large eddy simulation approach
- Inflow turbulence generation methods
- Street canyon
- Computational fluid dynamics
“CFD Simulation of Micro-Scale Pollutant
Dispersion in the Built Environment”, Building and
Environment, Vol. 64, pp. 225-230, 2013.
3. Bazdidi-Tehrani, F., Bodaghi, D., Kiamansouri, M.,
and Jadidi, M., “Turbulent Schmidt Number Effects
on Pollutant Dispersion in a Street Canyon”, The
23rd Annual International Conference on
Mechanical Engineering-ISME2015, Tehran, Iran,
May 2015.
4. Bazdidi-Tehrani, F., Mohammadi-Ahmar, A.,
Kiamansouri, M., and Jadidi, M., “Investigation of
Various Non-linear Eddy Viscosity Turbulence
Models for Simulating Flow and Pollutant
Dispersion on and Around a Cubical Model
Building”, Building Simulation, Vol. 8, No. 2, pp.
149-166, 2015.
5. Bazdidi-Tehrani, F., and Jadidi, M., “Large Eddy
Simulation of Dispersion Around an Isolated Cubic
Building: Evaluation of Localized Dynamic kSGSEquation
Sub-Grid Scale Model”, Environmental
Fluid Mechanics, Vol. 14, No. 3, pp. 565-589, 2014.
6. Bazdidi-Tehrani, F., Ghafouri, A., and Jadidi, M.,
“Grid Resolution Assessment in Large Eddy
Simulation of Dispersion around an Isolated Cubic
Building”, Journal of Wind Engineering and
Industrial Aerodynamics, Vol. 121, pp. 1-15, 2013.
8. Xie, Z. T., and Castro, I. P., “Efficient Generation of
Inflow Conditions for Large Eddy Simulation of
Street-Scale Flows”, Flow, Turbulence and
Combustion, Vol. 81, No. 3, pp. 449-470, 2008.
9. Jadidi, M., Bazdidi-Tehrani, F., and Kiamansouri,
M., “Dynamic Sub-Grid Scale Turbulent Schmidt
Number Approach in Large Eddy Simulation of
110 Dispersion around an Isolated Cubical Building”,
Building Simulation, Vol. 9, No. 2, pp. 183-200,
2016.
10. Jiang, G., Yoshie, R., Shirasawa, T. and Jin, X.,
“Inflow Turbulence Generation for Large Eddy
Simulation in Non-isothermal Boundary Layers”,
Journal of Wind Engineering and Industrial
Aerodynamics, Vol. 104, pp. 369-378, 2012.
11. Murakami, S., “Overview of Turbulence Models
Applied in CWE-1997”, Journal of Wind
Engineering and Industrial Aerodynamics, Vol. 74,
pp. 1-24, 1998.
12. Tamura, T., Okuno, A., and Sugio, Y., “LES
Analysis of Turbulent Boundary Layer over 3D
Steep Hill Covered with Vegetation”, Journal of
Wind Engineering and Industrial Aerodynamics, Vol.
95, No. 9, pp. 1463-1475, 2007.
13. Tominaga, Y., Mochida, A., Murakami, S., and
Sawaki, S., “Comparison of Various Revised k–ε
Models and LES Applied to Flow Around a High-
Rise Building Model with 1: 1: 2 Shape Placed
within the Surface Boundary Layer”, Journal of
Wind Engineering and Industrial Aerodynamics, Vol.
96, No. 4, pp. 389-411, 2008.
14.Wang, T., Cao, S., and Ge, Y., “Generation of Inflow
Turbulence using the Local Differential Quadrature
Method”, Journal of Wind Engineering and
Industrial Aerodynamics, Vol. 122, pp. 96-104,
2013.
15. Maruyama, T., “Surface and Inlet Boundary
Conditions for the Simulation of Turbulent Boundary
Layer over Complex Rough Surfaces”, Journal of
Wind Engineering and Industrial Aerodynamics,
Vol. 81, No. 1, pp. 311-322, 1999.
16.Kameda, H., and Morikawa, H., “Conditioned
Stochastic Processes for Conditional Random
Fields”, Journal of Engineering Mechanics, Vol.
120, No. 4, pp. 855-875, 1994.
17. Mathey, F., Cokljat, D., Bertoglio, J. P., and Sergent,
E., “Assessment of the Vortex Method for Large
Eddy Simulation Inlet Conditions”, Progress in
Computational Fluid Dynamics, An International
Journal, Vol. 6, No. 1, pp. 58-67, 2006.
18. Smirnov, A., Shi, S., and Celik, I., “Random Flow
Generation Technique for Large Eddy Simulations
and Particle-Dynamics Modeling”, Journal of Fluids
Engineering, Vol. 123, No. 2, pp. 359-371, 2001.
19.Kraichnan, R. H., “Diffusion by a Random Velocity
Field”, Physics of Fluids, Vol. 13, No. 1, pp. 22-31,
1970.
20. Lund, T. S., Wu, X., and Squires, K. D., “Generation
of Turbulent Inflow Data for Spatially-Developing
Boundary Layer Simulations”, Journal of
Computational Physics, Vol. 140, No. 2, pp. 233-
258, 1998.
21.Kataoka, H. and Mizuno, M., “Numerical Flow
Computation around Aeroelastic 3D Square Cylinder
using Inflow Turbulence”, Wind and Structures, Vol.
5, No. 2, pp. 379-392, 2002.
22.Kataoka, H., “Numerical Simulations of a Wind-
Induced Vibrating Square Cylinder within Turbulent
Boundary Layer”, Journal of Wind Engineering and
Industrial Aerodynamics, Vol. 96, No. 10, pp. 1985-
1997, 2008.
23.Gromke, C., Denev, J., and Ruck. B., “Dispersion of
Traffic Exhausts in Urban Street Canyons with Tree
Plantings-Experimental and Numerical Investigations”,
Procceding. of the International Workshop on
Physical Modelling of Flow and Dispersion
Phenomena, Vol. 1, 2007.
24. Sagaut, P., Large Eddy Simulation for
Incompressible Flows: An Introduction, Springer
Science & Business Media, 2006.
25.Germano, M., Piomelli, U., Moin, P., and Cabot, W.
H., “A Dynamic Subgrid‐Scale Eddy Viscosity
Model”, Physics of Fluids A: Fluid Dynamics (1989-
1993), Vol. 3, No. 7, pp. 1760-1765, 1991.
26. Lilly, D. K., “A Proposed Modification of the
Germano Subgrid‐scale Closure Method”, Physics of
Fluids A: Fluid Dynamics (1989-1993), Vol. 4, No.
3, pp. 633-635, 1992.
27. Tominaga, Y., and Stathopoulos, T., “Numerical
Simulation of Dispersion around an Isolated Cubic
Building: Model Evaluation of RANS and LES”,
Building and Environment, Vol. 45, No. 10,
pp. 2231-2239, 2010.
28. Tominaga, Y., and Stathopoulos, T., “CFD Modeling
of Pollution Dispersion in a Street Canyon:
Comparison between LES and RANS”, Journal of
Wind Engineering and Industrial Aerodynamics,
Vol. 99, No. 4, pp. 340-348, 2011.
29. Tominaga, Y., and Stathopoulos, T., “CFD Modeling
of Pollution Dispersion in Building Array:
Evaluation of Turbulent Scalar Flux Modeling in
RANS Model using LES Results”, Journal of Wind
Engineering and Industrial Aerodynamics, Vol. 104,
pp. 484-491, 2012.
30. Franke, J., Hellsten, A., and Schlunzen, K. H.,
Carissimo, B., “The COST 732 Best Practice
Guideline for CFD Simulation of Flows in the Urban
Environment: a Summary”, International Journal of
Environment and Pollution, Vol. 44, No. 1, pp. 419-
427, 2011.
31. Tominaga, Y., Mochida, A., Yoshie, R., Kataoka, H.,
Nozu, T., Yoshikawa, M., and Shirasawa, T., “AIJ
Guidelines for Practical Applications of CFD to
Pedestrian Wind Environment around Buildings”,
Journal of Wind Engineering and Industrial
Aerodynamics, Vol. 96, No. 10, pp. 1749-1761,
2008.
32. “GAMBIT 2.4 User’s Guide”, 2007.
33. “Ansys Fluent 15 Users’ Guide”, Ansys Fluent Inc,
111 روشهای عددی در مهندسی، سال ۳۵ ، شماره ٢، زمستان ١٣٩٥
2014.
34. “OpenFoam, The Open Source CFD Toolbox,
Programmer’s Guide ,Version 2.1.1”, Open CFD
Ltd., 9 Albert Road, Caversham, Reading, Berkshire
RG4 7AN, UK. 2011.
36.Hunter, L. J., Watson, I., and Johnson, G.,
“Modelling Air Flow Regimes in Urban Canyons”,
Energy and Buildings, Vol. 15, No. 3, pp. 315-324,
1991.
112
)