بررسي هيدروآيروديناميكي يك فويل فلپ دار در شرايط مرزي مختلف با استفاده از روش انتگرال مرزي و شبكه هاي عصبي مصنوعي

چكيده انگليسي :

Aerohydrodynamic Analysis of a Flapping Foil with Different Boundary Conditions by means of Boundary Integral Method and Artificial Neural Networks Alireza Jahanbakhsh a jahanbakhsh@me iut ac ir July13 2011 Department of Mechanical Engineering Isfahan University of technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Prof Ahmad Reza Azimian azimian@cc iut ac irAbstractIt is attempted in this thesis to show the use of various kinds of foils to be applied in aerodynamic andhydrodynamic applications Regarding to the growth of the use of the amount of Hydrofoils and Airfoilsin many industries the necessity of developing most efficient types of these foils is becoming moreobvious and thus many different methods related to this subject have been examined Since theirperformance is straightly related to the lift force due to the flow over the hydrofoils the biggest endeavorto increase the efficiency is concentrated on the increase of this force One approach to achieve this goalis to prepare certain boundary conditions for the foil One kind of these boundary conditions is the solidboundary condition in the proximity of the foil This solid boundary can be considered as a wall or as aflap or even as one or more foils in the vicinity of the main foil Sometimes other boundary conditionssuch as free surface boundary condition can be considered too In this project first of all we haveassessed the potential flow without any boundaries over a simple one part flapped and two part flappedairfoils by boundary element panel method and arrangement of some kinds of singular elements such assource doublet and vortex singularities with constant and linear forms of distribution Then to considerthe ground effect one of the above boundary conditions has been assessed for such foils and the resultsin the form of pressure coefficient and lift coefficient charts for certain foils is revealed Consequently the last mentioned boundary condition i e the free surface boundary condition was considered forcertain hydrofoils as mentioned previously while the flow over a simple one part flapped and two partflapped hydrofoil has been assessed as before It is worth mentioning that one of the goals of this projectwas to use the Artificial Neural Networks in association with boundary integral panel method to save timeand cost Therefore the Artificial Neural Networks have been used with boundary integral panel methodto abate time of the problem in the case of hydrofoil in the vicinity of free surface As it is known theArtificial Neural Network needs to be trained first To train the Artificial Neural Network used in thisthesis the Levenberg Marquardt algorithm is used After that the Artificial Neural Network is validated bysome part of data and then tested with the remaining data The process of choosing and utilizing theneurons and other details of this part is expressed in related parts of the thesis and also could be found inthe litrature Then the results of panel method in combination with Artificial Neural Networks for asimple and a two part flapped hydrofoil in the vicinity of the free surface are compared with the similarresults of panel method without using the Artificial Neural Networks Finally the use of Artificial NeuralNetworks in combination with other time consuming computational fluid dynamic methods and the useof other forms of ANN is suggested for future work Keywords Hydrofoil Boundary Integral Panel Method Singular Element Source Doublet Vortex Ground Effect Artificial Neural Network

جهان بخش، علي رضا

بررسي هيدروآيروديناميكي يك فويل فلپ دار در شرايط مرزي مختلف با استفاده از روش انتگرال مرزي و شبكه هاي عصبي مصنوعي

هيدروفويل , روش المان مرزي نيل , المان منفرد , چشمه , دابلت , ورتكس , اثر زمين , سطح آزاد