A new study published in Chinese Journal of Aeronautics reveals critical insights into hypersonic boundary layer instabilities. Using resolvent analysis, parabolized stability equations and direct numerical simulation, researchers investigated disturbance growth on a blunt-tip wedge at Mach 5.9. The study identifies two competing wave patterns: Pattern A (slow amplification in the entropy layer) and Pattern B (rapid transient growth in the boundary layer). Key findings highlight the impact of nose radius, wall cooling, and acoustic wave receptivity, offering new control strategies for nonmodal instabilities. This work advances understanding of hypersonic flow stability with practical implications for aerospace design.

Computational Fluid Dynamics (CFD) is a pivotal tool in modern engineering and scientific research. As simulation scale increases, computational acceleration for CFD have become a prominent focus. The implicit-explicit (IMEX) method partitions spatial regions to apply implicit or explicit methods, maintaining numerical stability while enhancing computational efficiency. Numerical results demonstrate that IMEX methods achieve efficiency improvements exceeding an order of magnitude compared to classical methods. In the future, coupling IMEX methods with GPU architectures will achieve greater computational speedups in extreme-scale simulations.

The rotating stall precursor is a major research focus in the field of aerodynamic compressor flow stability, as an accurate understanding of its physical mechanisms can help improve the operating margin of the compressor system in aircraft engines and ensure flight safety. With advances in numerical simulation techniques, the physical essence of spike-type stall has been increasingly investigated in depth. Many studies assume that weak-amplitude disturbances exist prior to stall and facilitate its onset; however, the specific nature of these disturbances, their relationship with the spontaneous unsteady behavior of the flow, and whether these disturbances serve as the origin of the spike-type stall, have yet to be clarified.

Researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and Columbia University, along with their collaborators, have analyzed sediments from the terrestrial Sangonghe Formation (Late Early Jurassic) in China's Junggar Basin, revealing information both on Solar System chaos and the global carbon cycle.