Design Of Pectoral And Caudal Fin Co-propulsion Bionic Fish And Its Hydrodynamic Performance

Therefore,some fishes have become bionic objects for researchers to study their swimming styles.However,in the current study of bionic fish,most researchers study BCF and MPF fish independently of each other;the current study of pectoral and caudal fin synergistic bionic fish is relatively single,often focusing only on its hydrodynamics and its coefficients,swimming speed and other performance indexes.To address the problems existing in current research,this thesis designs a pectoral and caudal fin synergistic propulsion bionic fish with plough ray,manta ray,tuna and dolphin as bionic objects.Numerical methods are used to investigate the effects of changes in pectoral and caudal fin motion parameters on the swimming performance of their three modes(pectoral and caudal fin modes,pectoral fin mode,and caudal fin mode),and the swimming performance of the three modes will be compared,while the effects of variable incoming current velocity on the hydrodynamic performance of the three modes will be investigated afterwards.Subsequently,the effect of changing pectoral and caudal fin motion parameters on the hydrodynamic performance of their pectoral and caudal fin modes will be investigated.Finally,the prototype test is designed and the test results are compared with the simulation results to verify the correctness of the simulation.The main research contents and results of the thesis are as follows:(1)By designing orthogonal experiments and using simulation software XFlow to simulate it numerically,the effect of pectoral and caudal fin motion parameters on its pectoral and caudal fin mode swimming performance(propulsion,speed,efficiency,transportation cost)is analyzed,and the combination of pectoral and caudal fin motion parameters is obtained at the best swimming performance.(2)design simulation experiments to analyze the effects of pectoral and caudal fin motion parameters on their swimming performance in pectoral and caudal fin modes,and compare the swimming performance of pectoral and caudal fin modes with that of pectoral and caudal fin modes.The comparison shows that the pectoral and caudal fin modes have more balanced swimming performance than the other two modes and have more advantages when swimming.(3)The incoming current velocity was added in the simulation environment to simulate the bionic fish disturbed by the current,and the effect of the change of incoming current velocity on the hydrodynamic performance of its three modes was investigated.The results show that when the incoming current velocity is less than 0.2 m/s,the propulsive force generated by the pectoral and caudal fin modes is greater than that of the caudal fin mode and greater than that of the pectoral fin mode,which can better combat the impact of the current.smooth and stable.(4)The effect of the variation of the pectoral and caudal fin motion parameters on the hydrodynamic performance of its pectoral and caudal fin modes is investigated.Finally,the prototype experiments are designed and the experimental results are compared with the hydrodynamic simulation results,and the error between them is below 20%,thus verifying the correctness of the hydrodynamic simulation.