Flow Structure for a Circular Cylinder with Exterior Surface Dimples

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2010 Vol.47, Issue 1 Preview Page Next Page

Flow Structure for a Circular Cylinder with Exterior Surface Dimples 외부 표면 딤플을 갖는 원형실린더의 유동구조: 박종명 , 윤치호
Jongmyung Park and Chi-Ho Yoon

28 February 2010. pp. 45-50

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Abstract

Dimples are employed on the exterior surface of the lifting pipe which is in the shape of a riser for reduction of drag forces. Water flow around a lifting pipe (circular cylinder) with exterior surface dimples is numerically predicted using version 6.3.26 of FLUENT. This numerical simulation is conducted in 3 cases. Case 1 shows the increases of momentum transportation in the dimple. Case 2 presents the validation of this simulation and the flow structure around the cylinder. And the flow structure in the dimple of the cylinder is investigated in Case 3. Spherical medium dimples (the dimple depth/the dimple print diameter=0.2) are located on the exterior of a circular cylinder. The new design presented in this research shows the lower drag coefficient of a dimpled cylinder compared to the data of a circular bare cylinder and velocity distribution is investigated in the dimple. This result is applied for design of the new lifting pipes and flexible hoses.

Keywords

Riser

Circular cylinder

Dimpled cylinder

Drag coefficient

Drag reduction

항력을 감소시키기 위하여, 심해저 채광을 위한 라이저 형태의 양광관 외부표면에 딤플구조를 사용하 였다. 양광관(원형실린더) 주위의 유체유동을 FLUENT 버전 6.3.26을 이용하여 예측하였다. 수치 해석은 3가지 경우에서 수행하였으며, Case 1은 딤플내에서 운동량 이송의 증가를 보여주었고, Case 2는 수치해석의 타당성 및 원형실린더 주위의 유동구조를 제시하였다. Case 3에서는 실린더 딤플 내에서의 유동구조를 분석하였다.심해저 망간간괴를 양광하는 파이프 외벽의 딤플구조는 본 연구에서는 원형의 중간형태의 딤플(딤플 깊이/딤플프린트 지름 = 0.2)을 사용하였으며, 이 딤플은 원형실린더 외벽에 위치한 형태이다. 이 연구에 제시된 새로운디자인의 딤플실린더는 원형의 실린더보다 낮은 항력계수를 보여주었고 딤플내의 속도 분포를 제시하였다. 이 결과는 저항력의 새로운 양광관 및 유연관 설계에 활용할 수 있을 것이다.

키워드

라이저

원형실린더

딤플 실린더

항력계수

항력 감소

References

Bearman, P.W. and Harvey, J.K. (1993), “Control of Circular Cylinder Flow by the Use of Dimples,” AIAA Journal, Vol. 31, No. 10, pp. 1753-1756.
Burgess, N.K., Oliveira, M.M., and Ligrani, P.M. (2003), “Nusselt Number Behavior on Deep Dimpled Surfaces within a Channel,” J. Heat Transfer, Vol. 125, No. 1, pp. 11-18.
Chung, J.S. (1994), “Advanced in Deep-Ocean Mining Systems Research,” Proceedings of 4th International Offshore and Polar Engineering Conference, pp. 18-31.
Chung, J.S., Whitney, A.K., Lezius, D., and Conti, R.J. (1994), “Flow-Induced Torsional moment and Vortex Suppression for a Circular cylinder with cables,” Proceedings of 4th International Offshore and Polar Engineering Conference, pp. 447-459.
Kimura, T. and Tsutahara, M. (1991), “Fluid Dynamics Effects of Grooves on Circular Cylinder Surface,” AIAA Journal, Vol. 29, No. 12, pp. 2062-2068.
Ligrani, P.M., Harrison, J.L., Mahmmod., G.I., and Hill, M.L. (2001), “Flow structure due to dimple depressions on a channel surface,” Physics of Fluids, volume 13, Number 11, pp. 3442-3451.
Sherrow, L., Ligrani, P.M., Chudnovsky, Y.P., and Kozlov, A.P. (2006), “Effects of exterior Surface Dimples on Heat Transfer and Friction Factors for a Cross-Flow Heat Exchanger,” Journal of Enhanced Heat Transfer, Volume 13, Number 1, pp. 1-15.
White, F.M. (1986), “Fluid Mechanics,” 2nd Edition, McGraw-Hill.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society for Geosystem Engineering
Journal Title(Ko) :한국지구시스템공학회지
Volume : 47
No :1
Pages :45-50

[1] Bearman, P.W. and Harvey, J.K. (1993), “Control of Circular Cylinder Flow by the Use of Dimples,” AIAA Journal, Vol. 31, No. 10, pp. 1753-1756.

[2] Burgess, N.K., Oliveira, M.M., and Ligrani, P.M. (2003), “Nusselt Number Behavior on Deep Dimpled Surfaces within a Channel,” J. Heat Transfer, Vol. 125, No. 1, pp. 11-18.

[3] Chung, J.S. (1994), “Advanced in Deep-Ocean Mining Systems Research,” Proceedings of 4th International Offshore and Polar Engineering Conference, pp. 18-31.

[4] Chung, J.S., Whitney, A.K., Lezius, D., and Conti, R.J. (1994), “Flow-Induced Torsional moment and Vortex Suppression for a Circular cylinder with cables,” Proceedings of 4th International Offshore and Polar Engineering Conference, pp. 447-459.

[5] Kimura, T. and Tsutahara, M. (1991), “Fluid Dynamics Effects of Grooves on Circular Cylinder Surface,” AIAA Journal, Vol. 29, No. 12, pp. 2062-2068.

[6] Ligrani, P.M., Harrison, J.L., Mahmmod., G.I., and Hill, M.L. (2001), “Flow structure due to dimple depressions on a channel surface,” Physics of Fluids, volume 13, Number 11, pp. 3442-3451.

[7] Sherrow, L., Ligrani, P.M., Chudnovsky, Y.P., and Kozlov, A.P. (2006), “Effects of exterior Surface Dimples on Heat Transfer and Friction Factors for a Cross-Flow Heat Exchanger,” Journal of Enhanced Heat Transfer, Volume 13, Number 1, pp. 1-15.

[8] White, F.M. (1986), “Fluid Mechanics,” 2nd Edition, McGraw-Hill.

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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