정온 비뉴톤 유체내에서 이동하는 원통형 물체의 항력계수비에 대한 직경비 및 길이비의 영향

조금남

Korean Journal of Rheology, Vol.6, No.1, 41-48, June, 1994

Export Citation

정온 비뉴톤 유체내에서 이동하는 원통형 물체의 항력계수비에 대한 직경비 및 길이비의 영향

Diameter and Aspect Ratio Effects on the Drag Coefficient Ratio of Cylinder Moving in Isothermal Non-Newtonian Fluids

조금남

초록

비뉴톤 유체내에서 이동하는 섬유들과 대분자들은 경우에 따라 일정한 길이와 직경을 갖는 원통형 물체로 간주될 수 있으므로 유체내에서 이들의 운동을 효과적으로 제어하기 위해서는 비뉴톤 유체내에서 이동하는 원통형 물체들의 길이비와 직경비에 의한 항력계수의 영향을 조사할 필요가 있다. 이러한 사실에 근거하여 원통형 물체의 길이비와 직경비 변화가 물체의 항력계수에 미치는 영향을 실험적으로 연구하는 것이 본 연구의 목적이었다. 원통형 물체들의 길이비를 기준으로한 항력계수비와 직경비를 기준으로한 항력계수비들은 작업유체로 사용된 일반화된 뉴톤 유체와 점탄성 유체내에서 이동하는 원통형 물체들의 길이비와 직경비가 증가함에 따라 감소했다. 윈통형 물체의 직경비가 0.007에서 0.029까지 변하고 길이비가 10에서 130까지 변하는 경우 점탄성용액내에서의 항력계수비의 감소율은 일반화된 뉴톤 유체내에서의 항력감소비의 감소율 보다 10배 내지 30배까지 더 컸다. 또한, 모든 작업유 체에서 원통형 물체들의 항력계수비들은 Reynolds수가 증가함에 따라 감소됐다.

The fibers and macromolecules moving in Non-Newtonian fluids may be considered as cylinders which have constant length and diameter in some cases. It is necessary to investigate the effects of the aspect ratio and the diameter ratio of cylinders on the drag coefficient in order to effectively control them moving in Non-Newtonian fluids. Based on that fact, the purpose of the present work experimentally investigate the effects of the aspect ratio and the diameter ratio of cylinders on the drag coefficient. The drag coefficient ratios based on the aspect ratio and the diameter ratio of cylinders were decreased as the aspect ratio and the diameter ratio of cylinders moving in generalized Newtonian fluids and viscoelastic fluids which were used as working fluids were increased. Their decreasing rates in viscoelastic fluids were approximately ten to thirty times larger than those in generalized Newtonian fluids when the diameter ratios and the aspect ratios of cylinders range from 0.007 to 0.029 and from 10 to 130, respectively. And, the drag coefficient ratios of cylinders were decreased as the Reynolds number was increased in all working fluids.

Keywords:Aspect ratio;diameter ratio;drag coefficient;drag coefficient ratio;viscoelastic fluid;reynolds number

[References]

Leal LG, "Annual Review of Fluid Mechanics," ed. by J.L. Lumley, M.V. Dyke, and H.L. Reed, Vol. 12, Annual Review Inc., Palo Alto, p. 435 (1980)
Probstein RF, "Physicochemical Hydrodynamics, An Introduction," Butterworths Publishers, Boston, p. 108 (1989)
Happel J, Brenner H, "Low Reynolds Number Hydrodynamics," Kluwer Academic Publishers, Dordrecht, p. 141 (1991)
Perrin F, J. Phys. Radium, 5, 497 (1934)
Burgers JM, "Second Report on viscosity and Plasticity," North Holland, Amsterdam (1938)
Broersma S, J. Chem. Phys., 32, 1632 (1960)
Tillett JPK, J. Fluid Mech., 44, 401 (1970)
Batchelor GK, J. Fluid Mech., 44, 419 (1970)
Cox RG, J. Fluid Mech., 44, 791 (1970)
Karnis A, Mason SG, Trans. Rheol., 10, 571 (1966)
Leal LG, J. Fluid Mech., 69, 305 (1975)
Chiba K, Song K, Horikawa A, Rheol. Acta, 25, 360 (1986)
Cohen C, Chung B, Stasiak W, Rheol. Acta, 26, 217 (1987)
Manero A, Mena B, Devargas L, Rheol. Acta, 26, 266 (1987)
Park NA, Irvine TF, J. Rev. Sci. Instrum., 59(a), 2051 (1988)
Cho K, Park B, Cho YI, Park NA, The Winter Annual Meeting of the ASME, FED-Vol. 124, 53 (1991)
Cho K, Chee D, Cho YI, The 5th Asian Congress of Fluid Mechanics, vol. 1, 25 (1992)
Chee D, Cho YI, Cho K, Lu P, Sep. Technol., Accepted and to be appeared in 1994 (1994)
Grossman PD, Soane DS, Anal. Chem., 62, 1592 (1990)
Tadmore Z, Bird RB, Polym. Eng. Sci., 14(2), 124 (1974)
Chen JLS, Kubler EA, Phys. Fluids, 21, 749 (1978)

[1] Leal LG, "Annual Review of Fluid Mechanics," ed. by J.L. Lumley, M.V. Dyke, and H.L. Reed, Vol. 12, Annual Review Inc., Palo Alto, p. 435 (1980)

[2] Probstein RF, "Physicochemical Hydrodynamics, An Introduction," Butterworths Publishers, Boston, p. 108 (1989)

[3] Happel J, Brenner H, "Low Reynolds Number Hydrodynamics," Kluwer Academic Publishers, Dordrecht, p. 141 (1991)

[4] Perrin F, J. Phys. Radium, 5, 497 (1934)

[5] Burgers JM, "Second Report on viscosity and Plasticity," North Holland, Amsterdam (1938)

[6] Broersma S, J. Chem. Phys., 32, 1632 (1960)

[7] Tillett JPK, J. Fluid Mech., 44, 401 (1970)

[8] Batchelor GK, J. Fluid Mech., 44, 419 (1970)

[9] Cox RG, J. Fluid Mech., 44, 791 (1970)

[10] Karnis A, Mason SG, Trans. Rheol., 10, 571 (1966)

[11] Leal LG, J. Fluid Mech., 69, 305 (1975)

[12] Chiba K, Song K, Horikawa A, Rheol. Acta, 25, 360 (1986)

[13] Cohen C, Chung B, Stasiak W, Rheol. Acta, 26, 217 (1987)

[14] Manero A, Mena B, Devargas L, Rheol. Acta, 26, 266 (1987)

[15] Park NA, Irvine TF, J. Rev. Sci. Instrum., 59(a), 2051 (1988)

[16] Cho K, Park B, Cho YI, Park NA, The Winter Annual Meeting of the ASME, FED-Vol. 124, 53 (1991)

[17] Cho K, Chee D, Cho YI, The 5th Asian Congress of Fluid Mechanics, vol. 1, 25 (1992)

[18] Chee D, Cho YI, Cho K, Lu P, Sep. Technol., Accepted and to be appeared in 1994 (1994)

[19] Grossman PD, Soane DS, Anal. Chem., 62, 1592 (1990)

[20] Tadmore Z, Bird RB, Polym. Eng. Sci., 14(2), 124 (1974)

[21] Chen JLS, Kubler EA, Phys. Fluids, 21, 749 (1978)