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Zekai Hong

Publications and source records attributed to Zekai Hong.

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Quasi-Two-Dimensional Simulation of a Rotating Detonation Engine Combustor and Injector

A numerical simulation of an annular rotating detonation engine with stoichiometric hydrogen-oxygen is performed. A generic, well posed, and easily implemented approach using a quasi-two-dimensional method to model the area variations through the rotating detonation engine's injector and combustor is presented. The detonation--injector interaction is studied for the case with a ratio of four between the combustor and injector's throat areas. A shock wave is formed in the divergent portion of the injector due the high back pressure created by the detonation in the combustor. A Favre-averaged steady-state analysis of stream lines and particle paths reveals that the shock causes an irrecoverable loss of stagnation pressure. Stagnation pressure gain in the combustor is insufficient to make up for the loss and the flow leaves the engine with lower stagnation pressure than in the plenum.

physics.flu-dyn

Islands on codim-2 branes in Gauss-Bonnet Gravity

We study the black hole information problem on codim-2 branes in Gauss-Bonnet gravity. Thanks to the island surface ending on the brane, the Page curve of eternal black holes can be recovered for all of the GB couplings within the causal constraints. Our results strongly support the universality of the island mechanism. Similar to Einstein's gravity, the HM surface can exist only in a finite time in GB gravity. Remarkably, for various parameters, the maximum times of HM surface are always larger than the Page times. As a result, the strange behavior of HM surfaces does not affect the Page curves for general GB gravity. Finally, we establish the correlation between the Page time, GB couplings, and brane tension, revealing that the Page time increases with these factors.

hep-th