Water Hammer Simulation Using Simplified Convolution-Based Unsteady Friction Model

Omission of frequency-dependent hydraulic resistance (skin friction) during modelling the water hammer phenomenon is unacceptable. This plays a major role when transient liquid flow occurs in rigid-walled pipes (steel, copper, etc.). In literature, there are at least two different approaches to skin friction. The first group consists models based on instantaneous changes local and convective velocity derivatives, second convolution integral full history flow. To date, more popular those from group, but their use requires empirical coefficients. still undervalued, even if good theoretical foundations does not require any undoubtedly related calculation complexity integral. this work, new improved effective solution further validated, which characterised with simplified weighting function consisting just exponential terms. approach speeds numerical calculations basic parameters (pressure velocity) significantly. Presented comparisons using procedure experimental pressure runs show usefulness proposed prove that it maintains sufficient accuracy.