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To study the influence of attack angle on ventilated supercavitating flow, a numerical model is established to simulate the supercavitation flow by using the inhomogeneous multiphase flow model and the SST k-ω turbulence model. And then, the model is verified and validated by comparing with the experimental results. The effect of attack angle on the profile of ventilated supercavity was numerically investigated over high Froude number. Results show that the attack angle causes the linear deviation of the ventilated supercavity axis, the deviation angle is in direct proportion to the attack angle, the deviation direction is opposite to the lift of the cavitator, and the deformation of the supercavity contour increases along the flow direction. The attack angle changes the gas flow structure inside the ventilated supercavity, causing the different deformation of the upper profile and lower profile. Under the condition of positive attack angle, the deformation of the lower profile of the supercavity generated by the disk cavitator is significantly greater than that of the upper profile.

In this paper, submerged gaseous jet-induced ventilated supercavity experiments were concluded in a closed-loop water tunnel. The study shows the impact of ventilation rates, nozzle area ratios, and modulated ventilation on cavity morphology and flow noise characteristics. The flow noise generated by the ventilated supercavity does not increase proportionally with the ventilation rates. The ventilated supercavity with vortex tube gas leakage structures induced noise haystacks in the 70–90 Hz band in both the self-noise and radiated noise spectra. When the gas input is large enough to foam a partially broken cavity (PBC), further increases in the ventilation rate result in a rapid deterioration in the self-noise performance. The nozzle area ratio influences the gas exit velocity, and therefore the interaction between the jet and the cavity. As the area ratio increases, the ventilation rate required to convert a supercavity from intact cavity (IC) pattern to PBC pattern increases, which improves its self-noise characteristics. Finally, the study conducted modulated ventilation in both foamy cavity and IC patterns. The results indicate that proper modulated ventilation can transfer noise energy from the low-frequency noise peak to the modulated frequency, reduce the low-frequency amplitude of the radiated noise, and improve the flow noise. [ABSTRACT FROM AUTHOR]

To investigate the unsteady shedding characteristics of a reentrant jet supercavity with a low Froude number, a high-fidelity numerical model based on the inhomogeneous multiphase model is developed to predict the complex supercavitation flow that occurs during supercavity development. The developed solver is validated quantitatively against experimental results in terms of supercavity geometry and closure mode. This study focuses on the initial generation and development process of a reentrant jet supercavity, revealing three distinct stages: foam cavity, transparent supercavity with rapid growth in dimensions, and fully developed supercavity exhibiting significant deformation. Owing to reverse flow of the gas–water mixture, interfacial instabilities arise from the unsteady cavity shedding, leading to fluctuations in supercavity shape. The types of large-scale cavity shedding observed in this work—wing-like and cloud-like—are caused by the concave deformation resulting from the reentrant jet. As the gas entrainment coefficient increases, the unsteady characteristics of pressure oscillation weaken, and the instance of wing-like cavities decreases. When the gas entrainment coefficient reaches a critical value, the twin-vortex closure mode occurs, resulting in a more stable flow behavior. In sum, we propose a theoretical model that elucidates the strength of the reentrant jet and reveals its unsteady shedding behavior during supercavity development. [ABSTRACT FROM AUTHOR]

To study the variation characteristic of supercavity shape and gas-leaking mode in the initial generation and development process of a ventilated supercavity, a 3-D numerical model considering the compressibility of the ventilated gas and gravity effect was adopted to simulate the supercavitation flow by using the inhomogeneous multiphase flow model and the SST turbulence model, which is verified and validated by the experimental results. The process of initial generation and development of the ventilated supercavity were investigated over a wide range of air entrainment coefficients and Froude numbers. The results show that the development of the re-entrant jet supercavity is very unstable. The initial generation of the supercavity is accompanied by the cavity collapse and cavity shedding, the phenomenon of air-water mixture reversely flowing occurs in the devolopment of the supercavity, and the supercavity shape is difficult to be estimated. The twin vortex supercavity is initially developed by the re-entrant jet closure mode. Then, the supercavity closure mode transfers to the twin vortex after the supercavity is fully developed, and the supercavity shape and the internal pressure are relatively stable. When approaching the criteria for the formation of the twin vortex and re-entrant jet closure, the supercavity mode changes between the twin vortex and the re-entrant jet, resulting in a more complex variation of supercavitation flow and supercavity shape.

Cucumbers are frequently affected by gray mold pathogen Botrytis cinerea, a pathogen that causes inhibited growth and reduced yield. Jasmonic acid (JA) plays a primary role in plant responses to biotic stresses, and the jasmonate-ZIM-Domain (JAZ) proteins are key regulators of the JA signaling pathway. In this study, we used the pan-genome of twelve cucumber varieties to identify cucumber TIFY genes. Our findings revealed that two CsTIFY genes were present in all twelve cucumber varieties and showed no differences in protein sequence, gene structure, and motif composition. This suggests their evolutionary conservation across different cucumber varieties and implies that they may play a crucial role in cucumber growth. On the other hand, the other fourteen CsTIFY genes exhibited variations in protein sequence and gene structure or conserved motifs, which could be the result of divergent evolution, as these genes adapt to different cultivation and environmental conditions. Analysis of the expression profiles of the CsTIFY genes showed differential regulation by B. cinerea. Transient transfection plants overexpressing CsJAZ2, CsJAZ6, or CsZML2 were found to be more susceptible to B. cinerea infection compared to control plants. Furthermore, these plants infected by the pathogen showed lower levels of the enzymatic activities of POD, SOD and CAT. Importantly, after B. cinerea infection, the content of JA was upregulated in the plants, and cucumber cotyledons pretreated with exogenous MeJA displayed increased resistance to B. cinerea infection compared to those pretreated with water. Therefore, this study explored key TIFY genes in the regulation of cucumber growth and adaptability to different cultivation environments based on bioinformatics analysis and demonstrated that CsJAZs negatively regulate cucumber disease resistance to gray mold via multiple signaling pathways. [ABSTRACT FROM AUTHOR]