A geometric perspective for the relativistic oblique shock structure is proposed. The proposed oblique shock geometry in angle-phase space may be helpful to better understand the physical structure of an interstellar shock.

No abstract

The difference between solarelastic interaction and aeroelastic interaction is illustrated from the perspective of external forces. Membrane solarelastic responses of the solar cell and solar sail are studied through a wave model and a corpuscular model of light, respectively, where the light intensity and phase are considered in the wave model to calculate the solar radiation pressure but the phase of light is neglected in the corpuscular model. The effects of the membrane optical properties, the thickness, and the size on the solarelastic flutter instability are investigated. The solar radiation pressure is divided into a part depending on the sail deformation and a part independent of sail deformation to investigate their respective influences. The results show that the former terms result in membrane flutter and the latter term results in membrane static deflection. A comparison is conducted between the wave model and the corpuscular model on the flutter boundaries and membrane responses. The membrane reflectivity is coupled with membrane stiffness by the membrane thickness in the wave model, but it is uncoupled in the corpuscular model. Therefore, the wave model has an advantage over the corpuscular model when evaluating the thickness effect of membrane reflectivity.

No abstract

An entropy decrease phenomenon in the shock wave is studied. The statistical entropy of a unit mass system (UMS) is constructed based on statistical mechanics. Two terms in the microscopic statistical entropy are connected with the macroscopic entropy increment. In order to obtain the number density and velocity distribution function of argon gas, the direct simulation Monto Carlo method is adopted. The physical mechanism for entropy decrease phenomenon in the shock layer is revealed as compression work winning internal energy to produce the heat loss of a UMS.