Abstract Vortex and vorticity are two correlated but fundamentally different concepts which have been the central issues in fluid mechanics research. Vorticity has rigorous mathematical definition (curl of velocity), no clear physical meaning. meaning (rotation) definition. For a long time, many people treat them as same thing. However, based on our high-order direct numerical simulation (DNS), we found that first, “vortex” is not “vorticity tube” or “vortex widely defined bundle lines...

Micro-vortex generators (MVGs) are widely utilized as passive devices to control flow separation in supersonic boundary layers by generating ring-like vortices that mitigate shock-induced effects. This study employs large eddy simulation (LES) investigate the structures a layer (Mach 2.5, Re = 5760) controlled two MVGs installed tandem, with spacings varying from 11.75 h 18.75 (h MVG height), alongside single-MVG reference case. A fifth-order WENO scheme and third-order TVD Runge–Kutta...

Shock oscillation with low-frequency unsteadiness commonly occurs in supersonic flows and is a top priority for the control of flow separation caused by shock wave boundary layer interaction. In this paper, interaction compression ramp vortex rings generated micro-vortex generator (MVG) at Ma = 2.5 simulated implicit large eddy simulation method. The analysis observation frequency both ring motion carried out. results show that produced has dominant non-dimensional low frequency, which...

This study investigated the ability of artificial neural networks (ANNs) to resolve nonlinear dynamics inherent in behavior complex fluid flows, which often exhibit multifaceted characteristics that challenge traditional analytical or numerical methods. By employing flow profile pairs are generated through high-fidelity simulations, encompassing both one-dimensional benchmark problems and more intricate three-dimensional boundary layer transition problem, this research convincingly...

A floating shock platform (FSP) is important experimental equipment for the antishock assessment of large‐scale shipborne equipment. Generally speaking, FSP a square barge structure with flat bottom. In order to satisfy key index horizontal‐to‐vertical ratio impact environment, special added mounted bottom platform, and environment more complicated due structure. Therefore, spherical factor theory proposed analyze validity proved by numerical experiments. The results show that average...

In this work, a vortex identification method is developed by analyzing the physical meaning of local rotation fluid elements. It shown that point locally rotational when velocity gradient tensor at has pair complex eigenvalues. The can be represented so called vector. direction vector defined as axis, which parallel to eigenvector corresponding real eigenvalue. magnitude evaluated twice minimum angular around among all azimuth in plane perpendicular Based on rotation, identified connected...

Shock-boundary layer interaction (SBLI) is frequently met in supersonic engine inlet flow and external flow. A detailed study on the mechanism of reduction shock induced separation by micro-vortex generator (MVG) carried out high order implicit large eddy simulation (ILES). To generate fully developed turbulent inflow, a series (20,000) profiles are given our previous DNS results. The MVG was originally considered as result streamwise vortex mixing. It thought that mixing would plump...

Based on the new theory of MVG to reduce separation caused by shock boundary layer interaction (SBLI), a optimization method is presented in this paper, mainly optimize location front shock. The key issue generate proper momentum deficit zone, which can strong shear and further vortex rings frequently, Several artificial zones (low speed streaks) are tested LES efficiency reduction SBLI induced assessed.

The intriguing similarity between the group multiplication table of a finite and Sudoku puzzle is worth exploring. A fundamental question arises: Can be induced from group? answer depends on context. Our primary finding, established through computer programming, indicates that puzzles generated by groups are rare, whereas tables Sudokus more common.

This study introduces a novel method to enhance numerical simulation accuracy for high-speed flows by refining the weighted essentially non-oscillatory (WENO) flux with higher-order corrections like modified compact scheme (MWCS). Numerical experiments demonstrate improved sharpness in capturing shock waves and stability complex conditions two interacting blast waves. Key highlights include simultaneous capture of small-scale smooth fluctuations precision surpassing original WENO MWCS...