OpenFlow-HAMMER-Connect Edition: Wave Spees in Polyethylene (PE) pipes

Question

Hi everyone 
 As I know the available developed formulas to calculate wave speed in pipes, are suitable for many various types of pipe materiales, but not for viscoelastic materials such as PE (polyethylene pipe ). 
 Do you know any reference to find/calculate the wave speed in PE pipes (or generally in viscoelastic materiales)? 
 
 Regards, 
 
 Hasan Meihami

Jesse Dringoli · Answer

Hi Hasan, 
 I am checking with my colleagues on this, but our Advanced Water Distribution Modeling and Management book mentions (page 588) that methods were proposed by "Covas et al. (2002)" to account for viscoelastic effects for materials like PE. From a web search, this might be the paper (though I am not certain). 
 However, using the standard Korteweg equation used by HAMMER's Wave Speed Calculator tool may be a good enough approximation for the purposes of transient simulations. One option to consider is a sensitivity analysis - try a range of values higher and lower than the values suggested by the wave speed calculator and compare the transient results to see if it is significantly impacted by the wave speed. If not, then this may indicate that you do not need to worry about accounting for viscoelastic effects. 
 I have added some information to the following related wiki article and will improve it further based on feedback from my colleagues. 
 Equation used in Wave Speed Calculator tool