ACG

The Aerothermal Coefficient Generator constructs databases of aerodynamic force and moment coefficients, and aerothermal heating coefficients for vehicle geometries. As well as being used for standalone analyses, when integrated within the Re-entry Casualty Risk module it can generate coefficients for new vehicle geometries resulting from fragmentation events.

  • Algorithms - ACG can make use of either a ray-tracing, or panel, method to generate shaded or unshaded coefficient databases.
  • Aerodynamic Models - Both free molecular and continuum aerodynamics are calculated at a range of speed ratios / Mach numbers. The classic formulation of Schaaf and Chambre is used for free molecular forces and moments. In the continuum regime the Modified Newtonian method is used. A full attitude dependent database, tumble averaged summary, or specific orientation data subset can be produced.
  • Aerothermal Models - Aerothermodynamic coefficients can be generated using the Modified Lees and Detra & Hidalgo sphere based pressure look-up formulae in continuum flows. Free molecular heating is based on accommodation to surface properties of the projected area.
  • Modular - The architecture of ACG permits the most appropriate components including the generation algorithm to be chosen from libraries at execution time.
  • Configurable - All aspects of ACG can be configured using JavaScript. This enables the tuning of fidelity versus execution time to be performed.
  • Portable - Written in a combination of Java and JavaScript, ACG is fully supported on Windows, Unix / Linux and OS X.