Water hammer simulation by explicit central finite difference methods in staggered grids

F. Khalighi, A. Ahmadi, A. Keramat

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

Four explicit finite difference schemes, including Lax-Friedrichs, Nessyahu-Tadmor, Lax-Wendroff and Lax-Wendroff with a nonlinear filter are applied to solve water hammer equations. The schemes solve the equations in a reservoir-pipe-valve with an instantaneous and gradual closure of the valve boundary. The computational results are compared with those of the method of characteristics (MOC), and with the results of Godunov's scheme to verify the proposed numerical solution. The computations reveal that the proposed Lax-Friedrichs and Nessyahu-Tadmor schemes can predict the discontinuities in fluid pressure with an acceptable order of accuracy in cases of instantaneous and gradual closure. However, Lax-Wendroff and Lax-Wendroff with nonlinear filter schemes fail to predict the pressure discontinuities in instantaneous closure. The independency of time and space steps in these schemes are allowed to set different spatial grid size with a unique time step, thus increasing the efficiency with respect to the conventional MOC. In these schemes, no Riemann problems are solved; hence field-by-field decompositions are avoided. As provided in the results, this leads to reduced run times compared to the Godunov scheme.

Original languageEnglish
Pages (from-to)69-77
Number of pages9
JournalJournal of Computational and Applied Research in Mechanical Engineering
Volume6
Issue number2
DOIs
Publication statusPublished - 2016
Externally publishedYes

Keywords

  • Godunov’s method
  • Lax-Friedrichs
  • Lax-Wendroff
  • Method of Characteristics
  • Nessyahu-Tadmor
  • Water hammer

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

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