Experimental and theoretical study of the effect of hull roughness on ship resistance

Soonseok Song, Saishuai Dai, Yigit Kemal Demirel, Mehmet Atlar, Sandy Day, Osman Turan

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)
121 Downloads (Pure)


Hull roughness increases ship frictional resistance and, thus, results in economic and environmental penalties. Its effect has been prevalently predicted using the similarity law scaling procedure. However, this method has not yet been validated with experimental data using a model ship. This study presents an experimental investigation into the effect of roughness on ship resistance and provides a validation of the similarity law scaling, by using tank testing of a flat plate and a model ship. Both the plate and the ship were tested in smooth and rough surface conditions, respectively. For the rough surface conditions, sand grit (aluminum oxide abrasive powder) was applied on the surfaces of the flat plate and the ship model. The roughness functions of the rough surface were derived by using the results obtained from the flat plate tests. Using the roughness function and the flat plate towing test, frictional resistance was extrapolated to the length of the model ship following the similarity law scaling procedure. The total resistance of the rough ship model was first predicted using the extrapolated frictional resistance and the result of the smooth ship model, and then compared with the results from the rough ship model. The predicted total resistance coefficients for the rough ship model showed a good agreement with the measured total resistance coefficient of the rough ship model, thus proving the validity of using Granville’s similarity law scaling to extrapolate the roughness effect on ship resistance.

Original languageEnglish
Pages (from-to)62-71
Number of pages10
JournalJournal of Ship Research
Issue number1
Early online date31 Aug 2020
Publication statusPublished - 17 Mar 2021


  • roughness effect
  • model ship towing test
  • Granville’s similarity law scaling
  • ship resistance
  • experimental fluid dynamics (EFD)


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