Added Mass Of Cylinders, Joukowski Airfoil And Constructions In Tandem With Them Based On Analytical Complex Potential

Added mass is one of the most important parameters affecting the force of objects moving in fluid,which can be used to study the dynamic characteristics of turbine,fish swarm,wing,torpedo,water boat and so on.To efficiently and accurately calculate the added mass of objects,putting forward the complex variable function method based on analytic complex potential,and then completely analytical formula of added mass is deduced.This calculation formula is substituted into Matlab for numerical integration,and finally the added mass is obtained.The calculation process has the advantages of high resolution,clear variable parameters and less time consuming,and the results are accurate and reliable.Based on analytical complex potential,added mass of the circular,elliptic cylinder,Joukowski airfoil,double cylinders in tandem arrangement,Joukowski airfoil and cylinder of tandem combination are mainly studied.The main work and results of this paper are as follows:(1)Using complex function method based on analytic complex potential,the added mass of the circular cylinder and elliptic cylinder are quite the same as the exact solution.Moreover,with the change of the Angle of the elliptic cylinder,the horizontal added mass of it is almost the same as the square solution based on its vertical height.(2)Through the rotation,translation and the joukowski mapping of the coordinates,the analytic complex potential of the joukowski airfoil is derived,which makes added mass obtained.it is shown that at ?=0,the added mass of the Joukowski airfoil increases with increasing,as well as ?,while at ?=?/2,the added mass increases with increasing or decreasing ?.The horizontal added mass of Joukowski airfoil and the solution based on square of vertical height of it have the same trend with the change of angle of attack.(3)Through milne-thomson circle theorem,the analytic complex potential of two circular cylinders with arbitrary radius ratio r and interval distance ? in the infinite ideal fluid is derived in detail.The change rules of the added mass of cylinder 1 are as follows:added mass M11 increases with increasing r,while decreases significantly with increasing ?.The larger the interval distance,the smaller the effect of cylinder 2 on cylinder 1.Added mass M11?1 when ?/b=4,which means the effect of cylinder 2 on cylinder 1 is negligible.(4)Comprehensive the derivation process of the complex potential of Joukowski airfoil and double circular cylinder in tandem arrangement,analytical complex potential of combination structure of Joukowski airfoil and circular cylinder in tandem arrangement,is derived and then we have the added mass.The relationships among added mass,radius of cylinder r and seperation distance s are as follows:the horizontal added mass and the vertical one of the Joukowski airfoil increase with increasing r,as well as ?,decreases significantly with increasing ?.When ?>5,the added mass is similar to that of a single airfoil,only 0.035%more than that.(5)Fluent was used to simulate the added mass of the above five structures.In order to simplify the setup and solving process,a self-compiled C program is used to set the motion of objects in the flow field,so as to systematize the added mass calculation process of arbitrary structures,and finally get the added mass of the objects.This method is compared to further verify the accuracy of the results of added mass based on the analytic complex potential.