This paper describes the analytical and experimental study of flow expansion due to resistance of a wire gauze placed in a parallel-sided channel. First, Taylor's source model was improved by introducing source-strength correction, and flow profiles and drag coefficients were calculated for various gauze heights. Next, measurements were also made on flow profiles and drag coefficients for resistance coefficients up to 20 in a smoke windtunnel. Consequently, agreement calculated and measured values was obtained. Furthermore, flow observation and velocity-distribution measurements were carried out for a model diffuser with high resistance coefficient wire gauze.