The effect of line averaging on concentration fluctuations

✍ Scribed by Steven R. Hanna

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 547 KB
• Volume: 40
• Category: Article
• ISSN: 0006-8314
• DOI: 10.1007/bf00116100

✦ Synopsis

The reduction in variance of concentration fluctuations due to line averaging is estimated assuming that the process is influenced by the integral distance scale, y,, of ambient turbulence and the scaling width, W, ofthe time-averaged plume. An analytical formula is derived for the line-averaged variance for situations where the autocorrelogram is exponential and the point variance decreases exponentially with distance from plume centerline. Predictions of concentration fluctuation variance are compared with water tank and field data, with the result that the decrease ofvariance with averaging distance is well-simulated if the model parameters y, and W are carefully chosen.