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Building Simulation: An International Journal

Article Title

Estimation of indoor contamination source location by using variational continuous assimilation method

Keywords

VCA, CFD, indoor air quality, data assimilation, source identification, steady calculation

Abstract

Information on concentration of contaminants is important for management of indoor air quality. Recently, data assimilation techniques are used in order to accurately estimate location and intensity of contamination source in addition to concentration field. In this study, the variational continuous assimilation (VCA) method, which was originally developed in meteorological simulations, was applied to estimates of indoor air quality. The method modifies the governing equations of computational fluid dynamics (CFD) model by adding a correction term which reduces the error between original CFD calculation and observed data. In the mass conservation equation, the correction term can be assumed to be a pseudo source term. The validity of VCA method was confirmed by numerical experiments for two-dimensional steady-state calculation with the following procedures: (i) “true” concentration field was produced by CFD calculations with “true” concentration source; (ii) “pseudo-observation” data were extracted from “true” concentration field; (iii) the VCA method was applied to “false” CFD calculations without contamination source to produce “corrected” concentration field using “pseudo-observation” data; (iv) “corrected” concentration field and contamination source were compared with “true” dataset. The numerical experiments revealed the following findings: the VCA method can identify the area where the contamination source was located; and the VCA method can also reduce errors between “true” and CFD-calculated concentration field although the peak concentration was not well-estimated. These results suggest that the VCA method is a utilizable method to estimate concentration field, and location and intensity of contamination source.

Publisher

Tsinghua University Press

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