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Large eddy simulation of wind-induced interunit dispersion around multistory buildings
1Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
Indoor Air
|March 20, 2015
Summary
Large eddy simulation (LES) reveals wider wind-induced interunit dispersion around buildings than previous models. Dispersion timescales are short, suggesting disease transmission is possible between building units.
Area of Science:
- Environmental Engineering
- Fluid Dynamics
- Building Physics
Background:
- Previous studies on interunit dispersion relied on Reynolds-averaged Navier-Stokes (RANS) models, yielding only mean dispersion patterns.
- Mean values from RANS may be inadequate for describing interunit dispersion due to the highly fluctuating nature of building envelope flows.
Purpose of the Study:
- To investigate wind-induced interunit dispersion around multistory buildings using transient large eddy simulation (LES).
- To compare LES dispersion routes and timescales with RANS simulations and natural ventilation/pathogen survival times.
Main Methods:
- Employed large eddy simulation (LES) for transient analysis of wind-induced interunit dispersion.
- Validated the LES model through experimental comparisons and sensitivity analyses.
- Compared dispersion routes and timescales against Reynolds-averaged Navier-Stokes (RANS) simulations and natural ventilation.
Main Results:
- LES results demonstrated significantly larger dispersion scopes compared to RANS simulations.
- The enhanced dispersion scope in LES is attributed to the fluctuating, stochastic nature of envelope flows, often averaged out in RANS.
- Interunit dispersion timescales were found to be comparable to natural ventilation rates.
Conclusions:
- Transient LES provides a more comprehensive understanding of interunit dispersion than RANS models.
- Interunit dispersion occurs rapidly, comparable to natural ventilation.
- The short timescales of interunit dispersion, relative to pathogen survival times, indicate a viable route for disease transmission between building units.
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