Dynamics of circular and rectangular jets in crossflow. (15th November 2021)

• Record Type: Journal Article
• Authors: Pokharel, Pranaya; Acharya, Sumanta
• Is Part Of: Computers & fluids. Volume 230(2021)
• Publication Date: 2021-11-15
• Subjects: Jet in crossflow -- Transverse jet -- Rectangular jet -- Axis switching -- Dynamic mode decomposition -- Large-eddy simulation; Fluid dynamics -- Data processing -- Periodicals; 532.050285
• DOI: 10.1016/j.compfluid.2021.105111
• Languages: English
• ISSNs: 0045-7930

Abstract

Highlights: Dynamic Mode Decomposition of circular and rectangular jets in crossflow. Large eddy simulations for turbulence in convectively unstable jets in crossflow. Axis switching in rectangular jets in crossflow depends on aspect ratio, direction. Vortex dynamics, breakdown and shedding of structures of jets in crossflow. Spectral analysis show dominance of shear layer frequencies in jets in crossflow. Dominant frequencies of rectangular jets in crossflow are higher than circular ones. Abstract: In this work, jets in crossflow (JICFs) were studied numerically through large-eddy simulation using a velocity ratio of 5.7 and a jet Reynolds number of 5000. A parabolic profile was used for the jet inlet and four specific cases were compared: one with a circular inlet and three with rectangular pipe inlets (aspect ratios: 2:1, 0.5:1, and 3:1) having the same mass flow rate of the jet. The results indicated that the rectangular JICFs penetrated the domain more deeply than the circular JICF and delayed the vortex and turbulence breakdown. The effect of the crossflow on the jet orientation was also studied and quantified, and modal analysis was conducted on the cases with dynamic mode decomposition. The significant modes were found to be consistent with spectral analysis of convectively unstable JICFs in the literature. The rectangular JICFs showed increased dominant modes frequencies compared to the circular JICF.