Information retrieval systems are very complex in nature due to the complex interaction of document, query, and matching subsystems involved in the process. Researchers working on developing new techniques to improve system performance typically use standardized document collections to test their techniques. This paper has a twofold objective. First, it presents a simulation model of the document information retrieval system. A simulation model can serve as a test-bed document collection that can be used by researchers in the area to test their techniques. A few experiments are run on this simulated collection to demonstrate the effect of varying queries, documents, and user requirements. Second, relevance feedback is employed in the model whereby the matching function used by the system, to match documents with queries, is progressively adapted to the preference function used by the user to judge relevance of the documents.