The International                        UPDATED 22nd May 2011
Journal of Ventilation
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June 2011 Edition of the IJV now Published  Call for Papers

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Paper 4:  Volume 5 No.1 June 2006 Edition

Development of a Simulator for Indoor Airflow Distribution in a Cross-Ventilated Building using the Local Dynamic Similarity Model

Tomoyuki Endo¹, Takashi Kurabuchi¹, Toshihiro Nonaka¹, Mizuki Ishii¹
Masaaki Ohba², Tomonobu Goto², Yoshihiko Akamine³

¹Tokyo University of Science , Japan .
²Tokyo Polytechnic University , Japan .
³University of Tokyo , Japan .

Abstract

In this study, the evaluation of cross ventilation is presented based on the simultaneous analysis of inside and outside conditions and for wind directions other than 0 degrees (i.e. for wind flow that is not aimed directly or normally to the inflow opening). The first part of the paper considers a conventional CFD analysis and compares the performance of the widely used k-ε turbulence model as well as the modified Durbin k-ε turbulence model. While a CFD approach can give good results it is very labour and computationally demanding. The second part of this paper consists of a description of a simplified approach based on the Local Dynamic Similarity Model. In the simplified approach, outdoor boundary conditions are established directly at the inflow opening by means of either wind tunnel experiment or CFD analysis of external flow conditions. Results of the simplified model are compared with experimental analysis and shown to give good agreement.  The method is also shown to be valid for single and multi room applications.

Key words:  computational fluid dynamics (CFD), k-ε model, wind pressure, cross-ventilation, local dynamic similarity model, indoor air flow, discharge coefficient, inflow angle.

References

Durbin PA: (1996). “On the k-3 stagnation point anomaly”. Int. J. Heat and Fluid Flow, 17, (1).

Endo T, Kurabuchi T, Ohba M, Akamine Y and Kamata M: (2004) “A Fundamental Study on the Airflow Structure of Outflow Openings”. International Journal of Ventilation, 2, (4): pp439-446.

Endo T, Kurabuchi T, Ishii M, Komamura K, Maruta E and Sawachi T: (2005) “Study on the numerical predictive accuracy of wind pressure distribution and air flow characteristics- Part1 optimization of turbulence models for practical use; Part2 prediction accuracy of wind pressure distribution of various shaped buildings. International Journal of Ventilation, 4, (3): pp269-284.

Kurabuchi T, Ohba M, Fugo Y and Endo T: (2002). “Local similarity model of cross-ventilation Part 1 modeling and validation”. The 8^th International Conference on Air Distribution in Rooms ‘ROOMVENT 2002’, pp613-616.

Kurabuchi T, Ohba M, Iwabuchi T and Shimada T: (2002) “Verification and streamtube analysis of simulated result of airflow of a cross-ventilated building for normal wind angle case. Analysis of airflow of cross-ventilated buildings based on LES and wind tunnel experiment (Part1)”. Journal of Architecture, Planning and Environmental Engineering (Transactions of AIJ). No.561, pp47-52.

Kurabuchi T, Ohba M, Endo T, Akamine Y and Nakayama F: (2004). “Local dynamic similarity model of cross ventilation part 1 – theoretical framework”. International Journal of Ventilation, 2, (4), pp371-382.

Kurabuchi T, Maruta E, Sawachi T and Fukuno A: (2004). “Numerical evaluation of wind pressure distributions of buildings by  means  of a  modified k-e model. The 9^th International Conference on Air Distribution in Rooms ‘ROOMVENT 2004’, pp303-304.

Kurabuchi T, Ohba M, Goto T, Akamine Y, Endo T and Kamata M: (2005). “Local dynamic similarity concept as applied to evaluation of discharge coefficients of cross-ventilated buildings – Part1 basic idea and underlying wind tunnel tests; Part2 applicability of local dynamic similarity concept; Part3 simplified method for estimating dynamic pressure tangential to openings of cross-ventilated buildings”. International Journal of Ventilation, 4, (3), pp285-300.

Kurabuchi T, Ohba M and Endo T: (2005) “Verification and streamtube analysis of simulated results of airflow of a cross-ventilated buildings for various wind incident angles. Analysis of airflow of cross-ventilated buildings based on LES and wind tunnel experiment (Part2)”. Journal of Environmental Engineering (Transactions of AIJ). No.591, pp7-13.

Murakami S, Mochida A, Kondo K, Ishida Y and Tsuchiya M: (1996). “Development of new k-e model for flow and pressure fields around bluffbody”. CWE96, Colorado, USA

Ohba M, Kurabuchi T, Fugo Y and Endo T: (2002) “Local similarity model of cross-ventilation Part 2 application”. The 8^th International Conference on Air Distribution in Rooms ‘ROOMVENT 2002’, pp617-620.

Ohba M, Kurabuchi T, Endo T, Akamine Y, Kamata M and Kurahashi A: (2004) “Local dynamic similarity model of cross ventilation part 2 – application of local dynamic similarity model”. International Journal of Ventilation, 2, (4), pp383-393.