No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Abstract
The study of high resolution method on accurate capture of shock and vortex wake remains one of the most challenging tasks in the computational fluid dynamics field. A numerical method is developed to simulate three dimensional compressible viscous transonic flow fields based on HLLC approximate Riemann solver. Convective terms of the Reynolds averaged Navier-Stokes equations are solved by HLLC solver. To improve accuracy, fifth-order weighted essentially non-oscillatory scheme is adopted. The scheme is carried out to compute flows around three dimensional fixed wings, and then successfully extended to the hovering rotor by combining the static overset grids where fifth-order interpolation directly performed in hole boundary conditions and artificial boundary conditions. Results obtained reveal that the developed method not only can well capture shock but also has high resolution for tip vortices.
... In this study, the unsteady flows over the supersonic parachute system (i.e., different canopy models with the same MSL capsule) are studied by numerically solving the 3-dimensional compressible N-S equations. The finite volume method is adopted for spatial discretization, and the HLLC (Harten-Lax-van Leer-Contact) scheme [24] is employed to calculate the inviscid flux term. Furthermore, the TVD polynomial interpolation scheme is used to avoid numerical oscillations. ...
The supersonic parachute plays an important role in the descent and landing of Mars missions. Next-generation supersonic parachutes, such as disksail parachutes, are alternatives to disk-gap-band (DGB) parachutes. Disksail parachutes have larger porous gaps and smaller porous seams on the canopy surface than DGB parachutes. To date, the influence mechanism of porous seams or gaps and their locations on the performance of supersonic parachute systems in Martian atmospheric conditions remains unclear. In this study, different canopy models with seams and gaps based on NASA’s supersonic disksail parachutes were designed, and the aerodynamic characteristics of such geometric porosity models were studied numerically. For seam-only models, the drag coefficient of the parachute decreases when the position of the seam is close to the middle of the canopy. When the seam is close to the mouth of the canopy, the pressure difference between the inner and outer surface of the canopy becomes small, reducing the risk of tearing the canopy. For gap-only models, the drag coefficient of the middle gap model is higher, while the lateral force stability of the top gap model is better. The results show that the addition of a seam can improve the drag performance of the top gap model and improve the lateral stability of the canopy with the middle gap. This study provides some theoretical references for designing the porosity of parachutes under different requirements for Mars exploration missions in the future.
... The supersonic flows around the parachute-like two-body model are solved numerically by the compressible N-S equations based on the finite volume method. The HLLC Riemann solver is used to evaluate second-order inviscid flux terms [19], and the viscous terms are calculated by the 2nd-order central differencing scheme. The coefficient of viscosity is computed according to Sutherland's law. ...
The supersonic flows around rigid parachute-like two-body configurations are numerically simulated at Mach number of 1.978 by solving three-dimensional compressible Navier-Stokes equations, where the two-body model consists of a capsule and a canopy, and a geometric structure (i.e., gap) is located on the canopy surface. The objective of this study is to investigate the effects of gaps with different porosities and positions on the aerodynamic performance of supersonic parachute. The complicated periodic aerodynamic interactions between the capsule wake and canopy shock occur around these two-body models. From the formation of canopy shock and drag coefficient variation, the cycled flow structures can be divided into three types:(1) narrow wake period, (2) open wake period, and (3) middle wake period. In addition, it was found that the geometric gaps have no obvious influences on the flow modes. However, compared with models with different gap positions, the two-body model with an upper gap (gap is close to the canopy vent, UG model) has a smaller drag coefficient fluctuation and better lateral stability. On the other side, the increase of porosity has a more significant impact on UG models.
ResearchGate has not been able to resolve any references for this publication.