Molecular Dynamics of Slow Viscous Flows
We use molecular dynamics techniques to study the microscopic aspects of several slow viscous flows past a solid wall, where both fluid and wall have a molecular structure. Systems of several thousand molecules are found to exhibit reasonable continuum behavior, albeit with significant thermal fluctuations. In Couette and Poiseuille flow of liquids we find the no—slip boundary condition arises naturally as a consequence of molecular roughness, and that the velocity and stress fields agree with the solutions of the Stokes equations. At lower densities slip appears, which can be incorporated into a flow—independent slip—length boundary condition. An immiscible two—fluid system is simulated by a species—dependent intermolecular interaction. We observe a static meniscus whose contact angle agrees with simple estimates and, when motion occurs, velocity—dependent advancing and receding angles. The local velocity field near a moving contact line shows a breakdown of the no—slip condition.
KeywordsContact Angle Contact Line Poiseuille Flow Slip Length Slip Boundary Condition
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- 9.G. Coccotti and W. G. Hoover, eds., “Molecular-Dynamics Simulation of Statistical Mechanics Systems” (North-Holland, Amsterdam, 1986).Google Scholar
- 10.J. M. Haile, “A Primer on the Computer Simulation of Atomic Fluids by Molecular Dynamics” (Clemson University, Clemson, SC, 1980).Google Scholar
- 14.J. Koplik, J. R. Banavar and J. F. Willemsen, Phys. Rev. Lett. 60, 1282 (1988); Phys. Fluids A 1, 781 (1889).Google Scholar
- 15.J. C. Maxwell, Phil. Trans. Roy. Soc. 170, 231 (1867); see also R. Jackson, “Transport in Porous Catalysts” (Elsevier, Amsterdam, 1977).Google Scholar
- 19.Y. Pomeau and A. Pumir, C. R Acad. Sci. 299, 909 (1984).Google Scholar
- 20.A. Nir, private communication (1988).Google Scholar
- 25.J. N. Israelachvili, “Intermolecular and Surface Forces” (Academic, London, 1985).Google Scholar
- 33.S. A. Mikhailenko, B. G. Dudar and V. A. Schmidt, Sov. J. Low Temp. Phys. 1, 109 (1975).Google Scholar
- 34.W. G. Hoover, D. J. Evans, R. B. Hickman, A. J. C. Ladd, W. T. Ashurst and B. Moran, Phys. Rev. A 22, 1690 (1980).Google Scholar
- 39.Although their solution cannot be correct down to the contact line, it can represent an outer or matching solution when combined with a slip boundary condition in the inner region near the wall; see Ref. 38.Google Scholar
- 42.G. K. Batchelor, “Theoretical and Applied Mechanics”, W. T. Kolter, ed. (North-Holland, Amsterdam, 1976).Google Scholar