7776

7241

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1391

يازده،159ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

احمد سوهانكار اصفهاني، احمدرضا زماني

شهريار منصور زاده

13/3/92

مهدي نيلي احمد آبادي، احمد صداقت

مهندسي مكانيك

ID7241

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Sensivity Analysis of Experimental Measurment of Drag Coefficient of an AUV in a Towing Tank Hamid Mansoubi Hosseini h mansoubihosseini@me iut ac ir 20th January 2013 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ahmad Sohankar Esfahani asohankar@cc iut ac ir Ahmad Reza Zamani arzamani@cc iut ac ir Abstract Autonomous underwater vehicle AUV is one of the most important vehicles in oceanographic applications and marine industry Determining the hydrodynamic forces acting on AUVs under deep water is a necessary part in design process of this type of vehicle In this work the drag coefficient of a research AUV developed in subsea research development center of Isfahan University of Technology is experimentally measured and sensitivity analyze of the measurement is carried out The effects of experimental parameters such as depth of force measurement strut type force sampling rate temperature and installation misalignments are investigated in the drag coefficient calculation via sensitivity analyze During this study the effect of various kinds of signal processing techniques on the accuracy of the results obtained for the signal of the drag force is also evaluated and discussed In addition hydrodynamic parameters are typically determined from physical model testing and there is usually some uncertainty concerning their exact values Therefore it is important to look at the sensitivity of the vehicle in terms of robustness how accurately does one have to know the parameters in order to ensure acceptable performance Thus the uncertainty of the experimental results is also determined and discussed in this work The measurements have also been used to validate results obtained for the drag force of the AUV from a CFD code that uses Reynolds Average Navier Stokes equations ANSYS CFX Different turbulence models on the results are tested and the best one is chosen for all further simulations Experiments and numerical simulations are performed for a range of Reynolds number ie 0 97 105 ReD 5 79 105 Also the experimental data obtained from experiments have been compared with the results obtained from numerical simulation and the existing semi empirical correlations Measurements have been performed for three kinds of struts with circular NACA0012 and NACA0018 cross sections and for five depths of 20 40 60 80 90 and 100 cm in a towing tank The results showed that the drag force smoothly increases with the model velocity The sensitivity of measured drag force for three kinds of struts is investigated The study showed that the results obtained with NACA0018 strut is more accurate than those with NACA0012 It is shown that this is due to the lower effect of the AUV model and the strut interaction It is also shown than the results obtain with circular strut is less accurate than those of the NACA s Sensitivity analysis of the parameters showed that the depth of the measurement and type of the Struts have more impact on the drag force measurements Key words Drag Coefficient AUV Sensitivity Analysis Uncertainty Assessment Experimental Method Numerical Method Towing Tank

احمد سوهانكار اصفهاني، احمدرضا زماني

شهريار منصور زاده

مهدي نيلي احمد آبادي، احمد صداقت