---

In this research, the plunging motion of an airfoil by a numerical method based on finite volume in different Reynolds numbers is simulated and the thickness effect, amplitude and reduced frequency on the aerodynamic coefficients are investigated. In this process, SIMPLEC algorithm, implicit solver, high order scheme and dynamic mesh method is used in unsteady simulation and the flow is supposed viscous, incompressible and laminar. Simulations are in three Reynolds 1000, 11000 and 50000, respectively, in accordance with the flight of the insects, small birds and pigeons are done in two amplitudes and three reduced frequencies. The simulation results are compared with published data to confirm the validity of research. This comparison shows comprisable agreement. Pressure distribution and Vortex shedding around airfoils show that the thickness of the airfoils delays vortex shedding and changes time-averaged thrust coefficient. Reduced frequency and amplitude of oscillation are two important parameters in this simulation, but the reduce frequency is more effective than amplitude. The response surface methodology (RSM) was used to optimize the plunging airfoil. Optimization shows that airfoil with 0.29% thickness, 3.08 reduced frequency and 0.5 dimensionless oscillating amplitude produce maximum trust coefficient.

---

In this study, the results of two optimized and base blades of a horizontal axis wind turbine with aeroelastic point of view are compared . In order to optimization, the chord length and the twist angle of the blade at various radiuses have been calculated by BEM. The Results which are obtained from 2D Computational Fluid Dynamics (CFD) have been utilized to train a Neural Network (NN). In the process of airfoil optimization, Genetic Algorithm (GA) is coupled with trained NN to attain the best airfoil shape at each angle of the attack. Finally, the optimized blade is derived. In order to simulate the flow on two blades and obtain the aerodynamic forces, the blades and their surrounding regions are organized by unstructured grid. The SIMPLE algorithm and second order upwind scheme are used in numerical fluid flow simulation. The aerodynamic forces on the blades have been used for stress and strain analysis. At this point, in addition to the aerodynamic forces, inertia forces resulting from the rotation of the wind turbine blade is also considered. The aerodynamic results show that optimized blade has high efficiency. The results of the analysis of the stress - strain showed that maximum stress on optimized blade is less than base blade and optimized blade design is also more reliable than the blade base.

---

The aerodynamic characteristics of nine configurations of supersonic continuous deflectable nose guided missiles have been investigated. Then the optimized geometry is achieved based on the maneuverability from aerodynamic and flight dynamic point of view. The studied configurations consists of a spherical nose tip, a tangent ogive, one set of stabilizing tail fins and a cylindrical body that its mid-section is flexible to form an arc of a circle. So the cylindrical body consists of a fix part in vicinity of nose, middle flexible part and main body with stabilizers. The effects of fix length and flexible length parameters on the aerodynamic and flight dynamics of guided missile have been studied. A code has been developed to solve full Navier-Stokes equations using finite volume and modified Baldwin-Lomax turbulence model. Multi-block technique is also used to solve main body and fin parts flow field. Further, a 3 degree of freedom code has been developed to compare planar flight dynamic of missiles. It is found that missiles with bigger lengths for fix and flexible parts show more aerodynamic maneuverability, but drag force grows concurrently. Flight dynamic analysis shows that drag effect is negligible and aerodynamic maneuverability analysis is compatible with flight maneuverability.

---

In first part of this study the methods of direct and indirect entering the effect of induced velocity in blade element theory to achieve lift force in hover flight of Drosophila flapping insect are investigated. Then a new algorithm for Induced velocity correction based on Rankin-Froude jet theory and direct method is presented. The results of previous and new methods to aerodynamic simulation of this insect in hovering flight with combined flapping and pitching angles were compared with published experimental results. The results of this comparison indicate that one of the models based on the indirect method as the best way to predict the experimental results. In second part of this work, the sensitivity of the instantaneous and mean force, produced by insect modeled wing, is examined with change in six wing important motion parameters. This parameters Includes: flapping frequency, phase difference between flapping and pitching angle, flapping and pitching amplitudes and flapping and pitching variations with respect to time in flapping cycle. The results show that with increasing frequency and flapping amplitude lift increasingly increases. Also, range of phase difference percent between flapping and pitching angle that lead to maximum lift of the wings is introduced. Results also show that with tending variation of flapping angle in cycle to sinusoidal trend, the lift force increases.

---

The flight dynamics of nine configurations of supersonic continuous deflectable nose guided missiles have been investigated. The studied configurations consist of a spherical nose tip, a tangent ogive, a set of stabilizing tail fins and a cylindrical body that its mid-section is flexible to form an arc of a circle. So the cylindrical body consists of a fix part in vicinity of nose, middle flexible part and main body with stabilizers. The effects of fix length and flexible length parameters on the flight dynamics of surface to surface, antiaircraft and antimissile missiles have been studied. A code has been developed to solve full Navier-Stokes equations using finite volume and modified Baldwin-Lomax turbulence model. Further, a 3 degree of freedom code has been developed to compare planar flight dynamics of missiles. This code consists of a guidance subroutine based on pure persuit law. The results show that even increase of fixed and flexible lengths enhance the maneuverability of the missile, but in some scenarios this can lead to increased flight time and more errors in the target engagement. Deflected nose relocates mass center away from the axis and a thrust vector torque is created. Study of surface to surface scenario shows that this torque improves accuracy of targeting and the ability of target dislocation. In air defense missiles, increase of Fix and Flex variables, will extend the limits of allowable firing angle. However, a heavy nose increases the role of thrust torque and subsequently decreases the role of nose geometry.

---

In this research, a new numerical approach which is capable of modifying the shape of three dimensional massive bodies like tall buildings respect to aerodynamic loads is presented; therefore, the aerodynamic forces are improved; consequently, the comfortability of the buildings is increased. This method is drawn into 2 parts; a numerical simulation of fluid flow and Adjoint method. As a result of it, some modifications are performed in the different parts of the building. In the primarily step, the building shape and its setting position are investigated in different flow conditions as effective parameters on the aerodynamic of buildings. Subsequently, the sensitivity level of each variable is studied on aerodynamic loads. The results illustrate that the building pattern has the highest impressments (76%) on the excited forces. In the next step, the amount of sensitivity of the fluid flow on the various areas of the tower is assessed by solving Adjoint equation in the whole fluid domain. As a result of that, some aerodynamic modifications are performed and it has been proved that the imposed loads on the tower have been declined around 31% whereas this amount of improvement is interested for designing of tall buildings.