A review of gas-surface interaction models for orbital aerodynamics applications

Abstract

Renewed interest in Very Low Earth Orbits (VLEO)-i.e. altitudes below 450 km-has led to an increased demand for accurate environment characterisation and aerodynamic force prediction. While the former requires knowledge of the mechanisms that drive density variations in the thermosphere, the latter also depends on the interactions between the gas-particles in the residual atmosphere and the surfaces exposed to the flow. The determination of the aerodynamic coefficients is hindered by the numerous uncertainties that characterise the physical processes occurring at the exposed surfaces. Several models have been produced over the last 60 years with the intent of combining accuracy with relatively simple implementations. In this paper the most popular models have been selected and reviewed using as discriminating factors relevance with regards to orbital aerodynamics applications and theoretical agreement with gas-beam experimental data. More sophisticated models were neglected, since their increased accuracy is generally accompanied by a substantial increase in computation times which is likely to be unsuitable for most space engineering applications. For the sake of clarity, a distinction was introduced between physical and scattering kernel theory based gas-surface interaction models. The physical model category comprises the Hard Cube model, the Soft Cube model and the Washboard model, while the scattering kernel family consists of the Maxwell model, the Nocilla-Hurlbut-Sherman model and the Cercignani-Lampis-Lord model. Limits and assets of each model have been discussed with regards to the context of this paper. Wherever possible, comments have been provided to help the reader to identify possible future challenges for gas-surface interaction science with regards to orbital aerodynamic applications.

CASPA-ADM: a mission concept for observing thermospheric mass density

“…Excellent and extensive reviews of aerodynamic modelling and gas-surface interaction models are presented by Mehta et al [27], Mostaza Prieto et al [31], and Livadiotti et al [21]. While the verification of aerodynamic modelling and gas-surface interactions using CASPA-ADM data needs to be studied in more detail and supported by simulations once the satellite design is in a more mature state, we outline here how this could in principle be achieved.…”

CASPA-ADM – a mission concept for observing thermospheric mass density

“…Excellent and extensive reviews of aerodynamic modelling and gas-surface interaction models are presented by Mehta et al [27], Mostaza Prieto et al [31], and Livadiotti et al [21]. While the verification of aerodynamic modelling and gas-surface interactions using CASPA-ADM data needs to be studied in more detail and supported by simulations once the satellite design is in a more mature state, we outline here how this could in principle be achieved.…”

RF Helicon-based Inductive Plasma Thruster (IPT) Design for an Atmosphere-Breathing Electric Propulsion system (ABEP)

“…Rarefied flows are described by the gas-kinetic Boltzmann equation, which is commonly solved numerically using the DSMC method [34]. Due to the few collisions that occur in rarefied flows, flow parameters are typically strongly dominated by wall interactions of the particles, in particular in VLEO [35]. Therefore, modelling the surface interactions of the particles as accurately as possible plays an important role in this flow regime and thus also in the design of the intake [36,37].…”

“…Figure 3: Mechanism of specular and diffuse re-emission [38] In specular reflections, particles rebound when hitting the surface without energy exchange, the angle of reflection equals the incident angle δ r = δ i , and the tangential component of particle velocity v t = v t remains constant. Only the normal velocity component vn = v n is affected undergoing a complete inversion v t → −v t .…”