Related Experiment Video
Updated: May 17, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Drag force and diffusion of small planar structures: A gas kinetic theory analysis and molecular dynamics study
Amitesh S Jayaraman1, Nikolaos Kateris1, Hai Wang1
1Stanford University, Department of Mechanical Engineering, Stanford, California 94305, USA.
None:
The drag force on planar structures of arbitrary shape is derived in free molecular flow using gas kinetic theory. The theory is formulated by considering the anisotropic intermolecular potential between the particle and gas molecules, in the limits of specular and diffuse scatterings. The drag force theory formulated by Dahneke [J. Aerosol Sci. 4, 147 (1973)10.1016/0021-8502(73)90066-9] for disklike bodies in free-molecular flow is shown to be a special case of the theory derived herein. The Einstein-Smoluchowski relationship is generalized with anisotropic drag to structures of arbitrary shape. Binary diffusion coefficients of planar molecules (benzene, naphthalene, phenanthrene, pyrene, coronene, and ovalene) in nitrogen are calculated using gas kinetic theory. The diffusion coefficients are in close agreement with available experimental data and with molecular dynamics simulations.
Related Concept Videos
Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
The Kinetic Model of Gases
Basic Postulates of Kinetic Molecular Theory: Particle Size, Energy, and Collision
Kinetic Molecular Theory and Gas Laws Explain Properties of Gas Molecules
Physical Principles Governing Gas Exchange
Gas Laws Governing Respiration
The behavior of gases is guided by Dalton's Law of partial pressures and Henry's Law.
Dalton's Law asserts that the total pressure exerted by...
Kinetic Theory of an Ideal Gas
The number of molecules in one mole is called Avogadro's number...

