IMPROVED METHOD FOR SIMULATING TRANSIENTS OF TURBULENT PIPE FLOW

The paper presents the problem of modelling and simulation of transients during turbulentfluidflowin hydraulicpipes. The instantaneous wall shear stress on a pipe wall is presented in the form of integral convolution of a weighting function and local acceleration ofthe liquid. This weighting function depends on the dimensionless time and Reynolds number. Its original, very complicated mathematicalstructure is approximatedtoasimplerformwhichisusefulforpracticalengineering calculations.ThepaperpresentsanefficientwaytosolvetheintegralconvolutionbasedonthemethodgivenbyTrikha(1975)forlaminarflow. An application of an improved method with the use of the Method of Characteristicforthecaseofunsteadyflow(waterhammer)ispresented. This methodis characterisedby highefficiencycomparedtotraditional numericalschemes.

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