Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 7 2021 09 23 Experimental Study of the Effect of Fluid Jet Swirl on Circular Hydraulic Jump Experimental Study of the Effect of Fluid Jet Swirl on Circular Hydraulic Jump 4153 4170 4082 10.22060/mej.2020.18409.6811 FA Ali Asadi Department of Mechanical Engineering, University of Birjand, Birjand, Iran Seyyed Majid Malek Jafarian Shahid Avini Ali Reza Teymourtash Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran Journal Article 2020 05 11 When an axially symmetrical fluid jet impacts on a horizontal plate vertically, a hydraulic jump is formed. Numerous studies are conducted on circular hydraulic jumps. However, the effect of the important and key parameter of fluid jet swirl on hydraulic jumps is not investigated. The main purpose of this study is to investigate the effect of this parameter on the circular hydraulic jump. The results of this study, achieved by using experimental method, show that the higher the angular velocity, the higher the increase in the radius of the jump. Drawing the diagram of the dimensionless radius of jump based on the dimensionless number of swirl shows two categories of lines. The first category is the constant angular velocity lines with a negative slope and the second category is the constant flow rate lines with a positive slope. The results showed that increasing the angular velocity of the swirling jet has less effect on increasing jump radius than increasing the flow rate. Experiments also showed that the hydraulic jumps created by a swirling jet follow the trend results of modified Watson’s theory with a non-significant difference. When an axially symmetrical fluid jet impacts on a horizontal plate vertically, a hydraulic jump is formed. Numerous studies are conducted on circular hydraulic jumps. However, the effect of the important and key parameter of fluid jet swirl on hydraulic jumps is not investigated. The main purpose of this study is to investigate the effect of this parameter on the circular hydraulic jump. The results of this study, achieved by using experimental method, show that the higher the angular velocity, the higher the increase in the radius of the jump. Drawing the diagram of the dimensionless radius of jump based on the dimensionless number of swirl shows two categories of lines. The first category is the constant angular velocity lines with a negative slope and the second category is the constant flow rate lines with a positive slope. The results showed that increasing the angular velocity of the swirling jet has less effect on increasing jump radius than increasing the flow rate. Experiments also showed that the hydraulic jumps created by a swirling jet follow the trend results of modified Watson’s theory with a non-significant difference. https://mej.aut.ac.ir/article_4082_02bf86214e264535e3412283e817deaa.pdf