Optimized Sensor Placement for Urban Flow Measurements
Abstract
We are interested in modeling the transport of contaminants in the atmospheric boundary layer, in complex geometries as in urban flow problems. One of our goals is to predict contaminant dispersion based on flow and concentration measurements using a minimum number of sensors. Since atmospheric flows are almost always turbulent, a direct approach would require a prohibitive number of sensors to resolve the important scales. The Proper Orthogonal Decomposition (POD) method provides an alternative method to describe a turbulent flow using a minimum amount of information. It allows us to decompose the flow field into temporal coefficients and spatial functions. If the temporal coefficients are obtained at a given instant of time, then, in principle, it is possible to reconstruct the entire threedimensional flow field exactly. A method has been developed that makes it possible to approximately compute these temporal coefficients from instantaneous velocity data taken at only a few locations simultaneously. Using the information of the spatial functions at the specified locations, a set of simultaneous equations are developed, which can be solved for the temporal coefficients. A quantitative comparison of the computed coefficients and the original coefficients shows that this method provides an accurate approximation of the temporal coefficients. Based on this method it will be possible to develop a practical approach of estimating the threedimensional turbulent flow field using velocity information from a small number of sensors.
 Publication:

APS Division of Fluid Dynamics Meeting Abstracts
 Pub Date:
 November 2003
 Bibcode:
 2003APS..DFD.FR002M