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This study investigates the energy budget of a viscoelastic planar liquid sheet in the presence of gas velocity oscillations. The energy budget is studied in different unstable regions, and the results are very different from those obtained for steady basic flow. The work done by surface tension and aerodynamic forces is periodic, leading to the growth of standing waves on liquid sheets. The positive work done by aerodynamic forces is the main cause of the instability, as for steady basic flow. However, treating the negative work of the surface tension as an increment in the surface energy is an effective means of determining the instability mechanisms. The unsteady basic flow causes the rate of change in the work done by viscosity and elasticity to vary periodically. An increase in elasticity and a decrease in deformation retardation promote the instability by increasing the work done by the gas medium, with reduced dissipation only as a secondary factor. This effect is more significant in parametric unstable regions than in the Kelvin–Helmholtz unstable region.

Buton rock asphalt (BRA) is possessed of both performance and economic advantages. In order to reveal the modification mechanism, X-ray diffraction experiment (XRD), X-ray fluorescence spectrum analysis and environmental scanning electron microscopy experiment (ESEM) are used to study on microstructure of BRA in this paper. It demonstrates that BRA can extremely adsorb free bitumen due to abundant microscopic pores, which consists of 70~80 percent Buton rock (BR) minerals and 20~30 percent pure rock asphalt (RA). RA with high viscosity is strongly adsorbed internal and outer of the surface of BR, which has high alkaline pH, high crystallization and strong surface activity. Then a special microstructure named “RA~BR” blend with stable property and strong spalling-resistance capability develops. Meanwhile, dynamic stability rheology test (DSR) is employed to study on the rheological mechanics property of BRA modified asphalt mastic. The high temperature performance grade (PG) level of BRA modified asphalt mastic with different mixing content is determined. The reasonable mixing content of BRA in matrix asphalt is 20~30 percent. The research proves that BRA modified asphalt possesses wonderful high temperature stability and has broad prospects for pavement application.