Combined effect of wave and current in rough bed free surface flow

Santosh Kumar Singh*, Pankaj Kumar Raushan, Koustuv Debnath

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In this paper, detailed experimental results are reported to study the effect of the surface wave of different frequencies on turbulent characteristics of flow over a regular array of cubical roughness. The velocity time series of current-only and combined wave-current flow is analyzed to obtain the distribution of first and the second order turbulence statistics, turbulent kinetic energy production, turbulent dissipation and kinetic energy fluxes at a fixed Reynolds number. To highlight the changes due to combined wave-current flow, a comparative study was made between the velocity profiles for current-only flow and those measured for combined wave-current flow. As expected, the rough profiles are shifted downwards with the amount equivalent to the roughness function (ΔU+), which was obtained directly from mean velocity profiles. Further, the thickness of turbulent boundary layer increases with the superposition of surface wave compared to current-only flow. Particular attention is also given to understand the behavior of kinetic energy flux to explicitly account for turbulent momentum transport characteristics over roughness under wave-current interactions.

Original languageEnglish
Pages (from-to)20-32
Number of pages13
JournalOcean Engineering
StatePublished - 15 Jul 2018
Externally publishedYes


  • Cubical roughness
  • Open-channel
  • Rough-bed
  • Turbulence
  • Wave-current


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