SGER: Optimal Solution of the Direct and Inverse Problems of Contaminant Dispersion

Illinois Institute Of Technology, Chicago IL

Investigators

Abstract

ABSTRACT PROPOSAL NO.: CTS-0350414 PRINCIPAL INVESTIGATORS: DIETMAR REMPFER INSTITUTION: ILLINOIS INSTITUTE OF TECHNOLOGY OPTIMAL SOLUTION OF THE DIRECT INVERSE PROBLEMS OF CONTAMINANT DISPERSION The general goal of this project is to develop practical methods for the prediction of the dispersive spread of contaminants in the atmosphere, and for the localization of the source of contaminants once they are detected. This problem can be solved in a satisfactory manner if a complete description of the velocity field of the atmosphere, both as a function of time and of space, is available. However, atmospheric flows are almost always turbulent, which means that large ranges of length and time scales are present in the flow. Thus, if one intends to measure these velocity fields by simply placing sensors on some regular grid that is fine enough to resolve the important length and time scales of the flow, one finds that a prohibitive number of sensors will be required. From these considerations it follows that it is necessary to obtain a description of the turbulent flow field that (a) requires a minimum amount of information, and (b) allows the highest possible accuracy in tracking, both backwards and forwards in time, the evolution of contaminant concentrations as a function of time. The method of Proper Orthogonal Decomposition (Lumley, 1971) has been developed as a means to describe turbulent flow fields using a minimal amount of information. The techniques associated with this method appear to be well suited also to achieve the second of the goals mentioned above. The accurate assessment and prediction of the dispersion of contaminants with a limited amount of resources is important both in the areas of environmental management and policy, as well as in the area of national defense against potential biological and/or chemical threats. After the terrorist attacks on the World Trade Center in September 2001, the national awareness of potential terrorist threats has undergone a significant change. Among prime areas of concern, in particular after the occurrence of several incidents involving agents of biological warfare (Anthrax spores) in the wake of the September 11 events, is the threat of terrorist attacks using chemical or biological agents. In order to defend against such attacks, it is important to have the capability to detect the occurrence of such an attack in a timely manner, and to locate the source of the attack as accurately as possible. A prime motivation of our project is the development of technologies and techniques that make it possible to achieve these goals.