Analysis of Water Hammer Attenuation in Applications with Varying Valve Closure Times

作者：Yao E; Kember G^*; Hansen D

来源：Journal of Engineering Mechanics, 2015, 141(1): 04014107.

DOI：10.1061/(ASCE)EM.1943-7889.0000825

• Water hammer
• Nonlinear
• Pressure wave attenuation
• Varying valve closure time
• Multiple scales analysis

A multiple scales asymptotic analysis is developed to describe the attenuation of a water hammer pressure wave initiated by a time-varying valve closure. The analytical results expose a simple rule-of-thumb relationship between water hammer pressure wave attenuation and the periodic average of the absolute flow velocity that is predicted by a quasi-steady friction model. The effect of flow reversals on the pressure wave attenuation is examined through comparison with a similar method applied to the water hammer generated during flow establishment, wherein flow reversals do not occur and there is a nonzero net flow. Although the analytical description is based on the assumption that the water hammer is generated by a sudden valve closure, its practical usefulness is extended by using the numerical solution as a guide to demonstrate its validity for a range of valve closure durations. A qualitative upper limit on closure times to which the analytic results may be applied is also found. All results are numerically verified using the method of characteristics.

• 出版日期2015-1