The unmanned aerial vehicle (UAV) is becoming popular from last two decades and it has been utilizing in enormous applications such as aerial monitoring, military purposes, rescue missions, etc. Hence, the present work focused on the design of the UAV wing considering the CH10 airfoil. In this paper, the computational fluid dynamic analysis on CH10 cambered airfoil has been conducted to achieve the preliminary results on the aerodynamic lift and drag coefficients. The airfoil has a chord length of 1 meter and has been subjected to low Reynolds numbers of 500 000, which is the standard operating Reynolds number for UAV wing design. The C-type fluid domain has been constructed at 30C upstream and downstream of the airfoil to initialize the boundary conditions. The angle of attack ranging from 0° to 14° with the increment of 2° has been done by changing the direction of the freestream velocity. The aerodynamic characteristics have been numerically computed using Spallart-Allmaras and Transient SST models. The aerodynamic coefficients achieved by these two models have been validated based on the XFOIL data. The contours of static pressure and velocity magnitude at 0°, 5°, 10°, and 12° angle of attack have been portrayed. The static pressure distribution around the airfoil has been visually observed to analyze its influence on the aerodynamic coefficients. The velocity magnitude relation to the static pressure distribution has been approved based on Bernoulli's equation such that increasing velocity magnitude has decreased the static pressure. The present results show that the Transient SST model has shown better flow prediction for an airfoil subjected to low Reynolds numberflow.

Accurate inertia properties information is important to reach an optimized estimation of attitude and precise control of a rigid spacecraft. Unfortunately, the satellite is succumbing several influences that can affect the inertia properties, such as fuel consumption and sloshing. Thus, this work inspects the use of star tracker to estimate the attitude, angular velocity and moment of inertia for a rigid nadir pointing satellite by employing extended Kalman filter, without any prior information about the nominal inertia matrix. The proposed estimator is applied in nadir pointing mode and without any constant control torque to avoid the attitude tumbling during the estimation phase, which in turn leads to a catastrophic failure of the satellite mission. The simulation results are compared to three other approaches and validated by Monte Carlo method that elucidates the good performance of the suggested approach and demonstrates its efficiency in satellite inertia tensor and attitude estimation even in worst situations.

This paper describes an investigation of the vibration of a cracked bio-composite beam reinforced with random short Alfa fibers using both analytical and experimental methods. The main novelty is the incorporation of local natural short fibers in the dynamic study of bio-based beams in the presence of a transverse crack. In addition, damping coefficient was predicted versus the crack length, crack position and fibers content. In the experimental model, tensile tests were made to predict Young's modulus and ultimate strength of specimens. After that, vibration tests were made to predict natural frequencies and damping coefficients versus crack depths, crack positions and fibers content. In the absence of similar experimental works on Alfa fibers, a simplified analytical model of flexural vibration has been developed to compare the results of experimental measurements. For different boundaries conditions, the linear fracture mechanics combined with Castigliano's theorem were used to estimate the local flexibility matrix at the cracked zone. For the natural frequencies, close agreement was found between the experimentally measured values and those given by the analytical model. From obtained results, we showed the increase in fiber content tends to reduce the strength and the natural frequencies of Alfa reinforced composite beams. Finally, we concluded that depth and position of the crack had a significant effect on the natural frequencies and damping coefficients of the bio-composite beam.

The goal of this research is to evaluate the stall behavior of a high aspect ratio rectangular wing in ground effect using an unsteady vortex-lattice method with a Kirchhoff-based correction (UVLM-K), including how the lift coefficient achieved in stall is affected by dynamic ground effect. A flow separation algorithm based on the Kirchhoff-Helmholtz theory and a flow separation model presented by Fischenberg are applied. The code was validated using experimental data from previously published works. The stall behavior of a rectangular wing of aspect ratio of 8.587 formed with a NACA 4415 airfoil section was studied in static and dynamic ground effect. To obtain the empirical data required by the UVLM-K, the NACA4415 airfoil was simulated at fixed height aboveground using a finite-volume code solver. The wing simulation results have shown that the lift coefficient achieved by the wing in stall for takeoff and flare maneuvers are lower than those estimated at a fixed height above the ground. It can be concluded, based on the results obtained herein, that the stall behavior of a wing in dynamic ground effect depends on the history of the maneuver.

The forthcoming use of Orion for Mars landing stimulated Zuppardi to compute global aerodynamic coefficients in rarefied flow along an entry path. Zuppardi and Mongelluzzo also studied Aerodynamics of a blunt cylinder, provided with flapped fins, as a possible alternative to Orion for Mars Entry, Descent and Landing. Computer tests were carried out, in the altitude interval 60-100 km, by three codes: i) home made code computing the entry trajectory, ii) Direct Simulation Monte Carlo code (DS2V), solving 2D/axisymmetric flow field and computing local quantities, iii) Direct Simulation Monte Carlo code (DS3V) solving 3D flow field and computing global aerodynamic coefficients. The comparison of the aerodynamic behaviour of the two capsules in axisymmetric flow field verified that heat flux and wall temperature for the finned-cylinder are higher than those of Orion. The DS3V results verified that Orion is better than the finned-cylinder to produce an aerodynamic force for slowing down the capsule. On the contrary, the results indicated that the finned-cylinder is better in terms of attitude control capability. The purpose of the present paper is to compare Aerodynamics of: Orion, finned-cylinder, a hypothetical, winged space-plane in high altitude Mars entry path. Computations were carried out by means of the two above mentioned DSMC codes, along both orbit and direct entry trajectories. While the global aerodynamic coefficients of the space-plane are comparable with those of the finned cylinder, the aerodynamic and thermal stresses (or pressure, temperature and heat flux) at the nose stagnation point are higher for the space-plane. Therefore, the finned-cylinder seems to be a valid alternative to Orion.