Shock wave

Turbulence

Aerodynamic drag

Parasitic drag

Heat transfer

Lift coefficient

Materials science

Mach number

Reynolds number

Heat flux

Range (aeronautics)

Drag

Classical mechanics

Scaling

Geology

Pressure coefficient

Oceanography

Physics

Lift-induced drag

Mathematics

Knudsen number

Flow (mathematics)

Zero-lift drag coefficient

Drag coefficient

Geometry

Particle (ecology)

Composite material

Mechanics

AIAA Journal

A generalized physics-based expression for the drag coefficient of spherical particles moving in a fluid is developed. The proposed correlation incorporates essential rarefied effects, low-speed hydrodynamics, and shock-wave physics to accurately model the particle-drag force for a wide range of Mach and Knudsen numbers (and therefore Reynolds number). Owing to the basis of the derivation in physics-based scaling laws, the proposed correlation embeds gas-specific properties and has explicit dependence on the ratio of specific heat capacities. The correlation is applicable for arbitrary particle relative velocity, particle diameter, gas pressure, gas temperature, and surface temperature. Compared with existing drag models, the correlation is shown to more accurately reproduce a wide range of experimental data. Finally, the new correlation is applied to simulate particle trajectories in high-speed dusty flows, relevant to a spacecraft entering the Martian atmosphere. The enhanced surface heat flux due to particle impact is found to be sensitive to the particle drag model.

General Drag Coefficient for Flow over Spherical Particles