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چکیده
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In present paper a model is presented for the bubble interaction. This model is based on the vortex generation caused by the presence of bubble in flow field. By the Newton’s third law when two objects interact, they exert equal and opposite forces on one another. This interaction between fluid and bubble will cause some changes in fluid properties such as the vorticity distribution. In present model two vortex blobs with equal and apposite strengths are located in specified positions around the bubble. A 2D fluid flow over a flat plate is considered and the Random Vortex Method (RVM) that is employed to solve the fluid phase has been coupled with the bubble interaction model. The bubble trajectory in outside and inside of boundary layer is computed furthermore the skin friction reduction by injecting 120 micro bubbles for ten Reynolds numbers between 103 and 104 is calculated. By the results as the Reynolds Number increases the drag reduction will increase logarithmically. Unfortunately neither experimental nor numerical data was found to verify the bubble trajectory. But some qualitative results and conclusions are presented for the bubble trajectory around a cylinder and over the flat plate. The results of fluid phase are verified by the experimental data and Blasius solution. The bubble dynamics comprises the drag, lift, added mass, pressure gradient, buoyancy and the wall effect. Weight of bubble and Basset force are neglected.
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