한국가시화정보학회지 (Journal of the Korean Society of Visualization)

  • 제16권3호
  • /
  • Pages.26-34
  • /
  • 2018
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  • 1598-8430(pISSN)
  • /
  • 2093-808X(eISSN)
한국가시화정보학회 (The Korean Society of Visualization)
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모형선 시험을 통한 외부경계층 수직 날 배열의 저항저감효과 검증

Verification of Drag Reduction Effect of Outer-layer Vertical Blades based on Model Test

  • 투고 : 2018.12.06
  • 심사 : 2018.12.24
  • 발행 : 2018.12.31
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초록

In the present study, an experimental assessment has been made of the drag reducing efficiency of the outer-layer vertical blades, which were first devised by Hutchins(1). A detailed flow field measurements have been performed using 2-D time resolved PIV with a view to enabling the identification of drag reduction mechanism. In addition, an experimental investigation has been made of the applicability of outer-layer vertical blades to real ship model. The arrays of outer-layer vertical blades have been installed onto the flat side and flat bottom of a 300k KVLCC model. A series of towing tank test has been carried out to investigate resistance (CTM) reduction efficiency with various geometric parameters and installed places of blades. The installation of vertical blades led to the CTM reduction of 1.44~3.17% near the service speed.

키워드

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Fig. 1. Schematic diagram of the circulating water tunnel

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Fig. 2. Vertical blades array installed in the test section

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Fig. 3. Vector plot and contour plot of streamwise velocity fluctuation in xz-plane at y = 1mm (y+ = 25); (a) without blade, (b) with blade

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Fig. 4. Vector plot and contour plot of streamwise velocity fluctuation in xz-plane at y = 4mm (y+ = 100); (a) without blade, (b) with blade

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Fig. 5. Vector plot and contour plot of streamwise velocity fluctuation in xz-plane at y = 9mm (y+ = 225); (a) without blade, (b) with blade

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Fig. 6. Blade geometry and naming convention

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Fig. 7. Photo of outer-layer vertical blades

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Fig. 8. 300K KVLCC2 model ship installed with acrylic boxes at side and bottom

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Fig. 9. Photograph of the bottom of 7, 11, 15 station installed vertical blades of various length

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Fig. 10. Total resistance with various blade (h/δ≈0.5) installation locations

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Fig. 12. EHP versus ship speed with various blade(h/δ≈0.5) installation locations

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Fig. 11. Effect of blade(h/δ≈0.5) installation locations on percentage CTM reduction

Table 1. Results of boudary layer thickness

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Table 2. Blade geometry variables: height

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Table 3. Blade geometry variables: spanwise packing

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Table 4. Principal particulars of KVLCC2

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Table 5. Comparison of CTM reduction by blade length (h/δ)

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참고문헌

  1. Hutchins, N., 2003, An investigation of larger-scale coherent structures in fully developed turbulent boundary layers, Ph.D. Thesis, University of Nottingham.
  2. IEA2016, 2016, CO2 emissions from fuel combustion highlights, International Energy Agency
  3. Corbett, J. J., Wang, H. and Winebrake, J. J., 2009, "The effectiveness and costs of speed reductions on emissions from international shipping," Transportation Research Part D, vol. 14, pp. 593-598 https://doi.org/10.1016/j.trd.2009.08.005
  4. Adrian, R. J., Meinhart, C. D. and Tomkins, C. D., 2000, "Vortex organization in the turbulent boundary layer," J. Fluid Mech., vol. 422, pp.1-54. https://doi.org/10.1017/S0022112000001580
  5. Park, H., An, N. H., Hutchins, N., Choi, K-S., Chun, H. H. and Lee, I., 2011, Experimental Investigation on the Drag Reducing Efficiency of the Outer-layer Vertical Blades, Journal of Marine Science and Technology, vol. 16, no. 4, pp.390-401 https://doi.org/10.1007/s00773-011-0135-0
  6. Moffat, R.J., 1982, Contributions to the theory of single-sample uncertainty analysis, Trans ASME J Fluid Eng, vol. 104, pp.250-260. https://doi.org/10.1115/1.3241818