2015
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Item Analysis of Wave Impact on Offshore Structure & Modeling a Physical Wave Creating Device(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2015-11-15) Mannan, Fahad; Imtiaz-Ur-Rahman, Md.; Hossain, Md. AlaminStructures in offshore seabed area is quite common affair.Offshore monopile foundation is one of the most commonly used foundation structures.The Sangu Gas field in Sangu river is an example in our country.These offshore structures are subjected to continuous cyclic load impact caused by sea waves which may cause structural failure and collapse. In this work, a developed numerical method for water-wave body interaction is used to study the water wave’s effects on the structural behavior of the monopiles. A validation procedure will be conducted by comparing the numerical results with analytical wave mathematical model results. The numerical model is based on Reynolds Averaged Navier Stokes equations (RANS) considering the effects of energy dissipation. ANSYS CFX is used to solve (RANS) using finite volume method. The free surface displacements are tracked by the volume of fluid method. The numerical model is used to simulate periodic first order waves and their interaction with a vertical slender monopile. The physical analysis is to be performed in a wave tank model where artificial waves is created using slider crank mechanism operated by an A.C motor.The offshore obstacles considered in the analysis were two types:- cylindrical monopile and square shape monopile.Item Study of a Convective Heat Transfer for Laminar and Turbulent Flow of Nano-fluid through a Circular Pipe(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2015-11-15) Mehmood, Aqib; Ismail, Motapon Njikam; Ndiaye, BabacarItem 3D CFD based optimization technique for muffler design of a motorcycle(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2015-11-15) Shadman, Sakib; Abir, Oneeruddho HussainIn order to minimize the sound transmission due to exhaust gases, the most common and important part of the engine system is muffler. A back pressure on engine is always produced due to the use of the exhaust muffler. This back pressure represents the extra static pressure exerted by the muffler on the engine through the restriction in flow of exhaust gases. The back pressure mainly depends on the internal shape and overall design of the exhaust muffler. Design of muffler is a complex function that affects noise characteristics, emission and fuel efficiency of engine. In this study, a combined model of response surface methodology (RSM) and desirability analysis is used for optimizing the back pressure of a motorcycle reactive muffler, in order to improve the performance of the muffler. For this optimization process, the design variable parameters are size of perforation, number of perforation and partition chamber size. To measure the back pressure 3D CFD based CAE software has been used. Prediction of acoustics transmission loss virtually is an important analysis required for the development of muffler at an initial design stage. For this reason, for the optimized design virtual acoustics transmission loss analysis is conducted. It is found that after optimizing the design of the muffler, the back pressure is decreased and the acoustic transmission loss is increased that can ensure the improvement of the muffler efficiency.Item Study of Effect of Different Burnishing Conditions on Surface Roughness for a Flexible Burnishing Tool(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2015-11-15) Hossain, Tapos; Tuser, Md. Towkir Ahmed; Ovy, S.M. Al IslamBurnishing is a very simple and effective method for improvement in surface finish and can be carried out using existing machines, such as lathe. Quality of Surface is an important factor to decide the performance of a manufactured product. For better quality surface finish the main factor is surface roughness. On account of its high productivity, it also saves more on production costs. Moreover, the burnished surface has a high wear resistance and better fatigue life. The lower value of roughness gives higher surface finish for the manufactured product. Now in present scenario different processes like grinding, honing, super finishing, polishing, burnishing etc are used to reduce the value of surface roughness. Burnishing is one of the processes which majorly affect the surface roughness. The levels of input process parameters are selected on basis of one factor at a time experiment are Depth of cut, burnishing feed, burnishing speed and number of passes.