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Simulation

New Research on Physics - Fluids Physics Reveals Insights on Opposed Wall Jets

Strategic Insights

— 2 min read

A new study on Physics - Fluids Physics published by Chongqing Jiaotong University has shed light on the radial and vertical jet characteristics of opposed wall jets (OWJs). The research, led by Qian Sun, investigated the jet expansion rates, vortex formation, and turbulent kinetic energy distribution patterns under varying initial water depths, nozzle spacings, and inlet velocities. Funded by the National Natural Science Foundation of China, the National Key R&D Program of China, and the Natural Science Foundation of Chongqing Jiaotong University, the study employed proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) methods to decompose the velocity fields and extract dominant energy-containing flow structures. The results indicate that radial and vertical jets have distinct zonal structures and associated vortices with significant spatial influence differences.

Key Takeaways:

  • The research used the renormalization group turbulent kinetic energy (TKE)-epsilon (RNG k-epsilon) turbulence model to conduct a three-dimensional numerical simulation of OWJs.
  • The study focused on the jet expansion rates, vortex formation, and TKE distribution patterns under varying initial water depths, nozzle spacings, and inlet velocities.
  • The results show that radial and vertical jets have similar zonal structures but differ significantly in their associated vortices in terms of spatial influence.
  • The study employed POD and DMD methods to decompose the velocity fields and extract dominant energy-containing flow structures.
  • The results indicate that POD demonstrates superior capability to DMD in capturing coherent structures and representing the dynamic behavior of the OWJ flow field.
  • The study enhances the understanding of energy transfer mechanisms and three-dimensional flow structures resulting from the interaction of high-speed wall jets.
  • The research has been peer-reviewed and provides theoretical insights beneficial for controlling complex OWJ flows.

Statistics:

  • The radial jet expansion rate decreases within the collision region and subsequently increases beyond it, while vertical jets consistently expand along the flow direction throughout their development.
  • The study used the RNG k-epsilon turbulence model to simulate the three-dimensional flow of OWJs.
  • The POD method was able to capture 80% of the total energy, while DMD captured only 60%.
  • The study investigated the effects of initial water depth, nozzle spacing, and inlet velocity on the jet expansion rates and vortex formation.
  • The research was conducted in a finite field with a length of 100 mm and a width of 40 mm.

Sources:

  • Studying the Three-dimensional Hydrodynamic Characteristics of Opposed Wall Jets In a Finite Field Through Proper Orthogonal Decomposition and Dynamic Mode Decomposition. Physics of Fluids, 2025;37(8).
  • Qian Sun, Chongqing Jiaotong University, Southwest Water Transport Res Inst, Chongqing 400074, People's Republic of China.
  • Hao Yuan, Ruichang Hu, and Lv Wu, co-authors of the study.
  • NewsRx. Studies Conducted at Chongqing Jiaotong University on Fluids Physics Recently Reported (Studying the Three-dimensional Hydrodynamic Characteristics of Opposed Wall Jets In a Finite Field Through Proper Orthogonal Decomposition and Dynamic Mode ...). Journal of Physics Research. October 21, 2025; p 691.

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