Hypersonic simulations using open-source CFD and DSMC solvers

Abstract

Hypersonic hybrid hydrodynamic-molecular gas flow solvers are required to satisfy the two essential requirements of any high-speed reacting code, these being physical accuracy and computational efficiency. The James Weir Fluids Laboratory at the University of Strathclyde is currently developing an open-source hybrid code which will eventually reconcile the direct simulation Monte-Carlo method, making use of the OpenFOAM application called dsmcFoam, and the newly coded open-source two-temperature computational fluid dynamics solver named hy2Foam. In conjunction with employing the CVDV chemistry-vibration model in hy2Foam, novel use is made of the QK rates in a CFD solver. In this paper, further testing is performed, in particular with the CFD solver, to ensure its efficacy before considering more advanced test cases. The hy2Foam and dsmcFoam codes have shown to compare reasonably well, thus providing a useful basis for other codes to compare against

A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part Two: Multi-Dimensional Analysis

“…In the wake of the cylinder, however, T tr is generally smaller using DSMC. Unlike the non-reacting simulation that demonstrated a good agreement for the vibrational temperature field in the compression area [5], the discrepancies in Figure 4d are much larger this time in the whole domain when compared with DSMC. This can be explained by the application of the QK theory to capture the chemistry-vibration coupling and the use of the quantum Larsen-Borgnakke method in dsmcFoam, which promotes a quicker energy harmonisation in expansion regions (where T v > T tr ) as reported in [4] using a zero-dimensional analysis.…”

“…It is normally evident that the bow shock is more diffuse when using the DSMC method compared with CFD. However, it is evident that the shock stand-off distances are almost identical using both solvers and are approximately equal to 0.25 m, which is about 5 cm closer to the body than for the non-reacting case [5]. The peak in trans-rotational temperature is correctly determined using the CVDV-QK combination for both runs 1 and 2 and is slightly over-predicted using the Park combination.…”

“…The set-up for this case can be found in the Supplementary Materials. The DSMC configuration is provided in [5], and good DSMC practice was satisfied for both the mesh and time-step. In the DSMC mesh, a total of 5.5 million cells were employed, which were filled with over 80 million equivalent DSMC particles at steady-state.…”

“…In the DSMC mesh, a total of 5.5 million cells were employed, which were filled with over 80 million equivalent DSMC particles at steady-state. Non-reacting case scenarios were also executed in [5], and the analysis will not be repeated here, although some of the results will be reported in the following graphs and tables.…”

An open-source hybrid CFD-DSMC solver for high speed flows

“…However, rhoCentralFoam, as a one-temperature solver without chemical modelling, lacks this capability. For this reason, the James Weir Fluids Laboratory at the University of Strathclyde is currently developing a two-temperature solver called hy2Foam [12,13].…”