Simplified procedure to evaluate liquid column separation phenomena

There are several procedures available for evaluating liquid column separation phenomena in horizontal penstocks. Some are complicated and offer accurate results; others are simple, but give results that are too approximate. Methods dealing with air inclusion problems are lacking. In this article it is shown that with some slight modifications it is possible to employ the method of characteristics for analyzing liquid column separation problems. For transient pressure surges, the authors have found that during the first three steps, the results evaluated using the proposed method agree with measurements performed in the laboratory, both in magnitude and time.