Computational Fluid Dynamic Analysis of Vortex Generators on MAV.

Micro Vortex generators are very small components deployed on the wings to control airflow over the upper surface of the wing to affect the boundary layer over it. These are employed onto a Micro aerial vehicle (MAV) of fixed wing type with an S5010 which is a low Reynolds number airfoil. This airfoil provides good aerodynamic results as compared to many low Reynolds number airfoils. Micro vortex generators are used to enhance the performance through controlling airflow at different speeds and angle of attack. The comparison of a half part of the MAV wing which is designed in CATIA, with and without the vortex generators on its leading edge at 10% of its chord length is done to show how the vortex generators improve the performance and control authority at different speeds and angle of attacks. These are shown with the velocity and pressure distribution around the wing by considering laminar flow in the simulation.

Computational Fluid Dynamic Analysis of Conceptual 3D Car Model

From past decades, people are giving more attention to conservation of the fuels. The increasing number of passenger cars have increased the amount of traffic which directly impacts pollution and traffic congestion. Manufacturers are indulged into making lightweight and performance efficient automobiles. Implementation of different designs and materials has been in practice since ages. We need smaller vehicle designs for personal transport and electric vehicles to tackle the raising problems. In future designs, vehicles will be efficient enough to save more fuel and also the traffic problems may be solved. But for the design optimizations and experiments we need different analyses to be performed, one of which is aerodynamic analysis. In this paper a CFD analysis is done to check the aerodynamic performance of a proposed car design. The car has been designed using Onshape modeling software and analyzed in Simscale software. The car is subjected to different vehicle speeds and the results of drag coefficients and pressure plots are shown. Keywords: Design and analysis of a vehicle, CFD analysis, Aerodynamic analysis, 3D modelling, Drag coefficient, Pressure plot, Concept car, Performance Optimization.

Computational fluid dynamic analysis of the initiation of cerebral aneurysms

OBJECTIVE Relationships between aneurysm initiation and hemodynamic factors remain unclear since de novo aneurysms are rarely observed. Most previous computational fluid dynamics (CFD) studies have used artificially reproduced vessel geometries before aneurysm initiation for analysis. In this study, the authors investigated the hemodynamic factors related to aneurysm initiation by using angiographic images in patients with cerebral aneurysms taken before and after an aneurysm formation. METHODS The authors identified 10 cases of de novo aneurysms in patients who underwent follow-up examinations for existing cerebral aneurysms located at a different vessel. The authors then reconstructed the vessel geometry from the images that were taken before aneurysm initiation. In addition, 34 arterial locations without aneurysms were selected as control cases. Hemodynamic parameters acting on the arterial walls were calculated by CFD analysis. RESULTS In all de novo cases, the aneurysmal initiation area corresponded to the highest wall shear stress divergence (WSSD point), which indicated that there was a strong tensile force on the arterial wall at the initiation area. The other previously reported parameters did not show such correlations. Additionally, the pressure loss coefficient (PLc) was statistically significantly higher in the de novo cases (p < 0.01). The blood flow impact on the bifurcation apex, or the secondary flow accompanied by vortices, resulted in high tensile forces and high total pressure loss acting on the vessel wall. CONCLUSIONS Aneurysm initiation may be more likely in an area where both tensile forces acting on the vessel wall and total pressure loss are large.

Structural and CFD Analysis of Unmanned Aerial Vehicle by using COMSOL Multiphysics

The purpose of this article is to reduce the structural weight and drag of an unmanned aerial vehicle (UAV) or drone while increasing its endurance. To achieve a high strength to weight ratio, Finite Element Analysis is used to study the structural strength characteristics of UAV frames. A computational fluid dynamic analysis (CFD) is performed for different angles of attack and vehicle speeds to estimate the drag coefficient using the k-e turbulence model. The analysis results show that the designed UAV vehicle has excellent performance characteristics and stability at 5° AoA and 3 m/sec. This article outlines the overall design of the unmanned aerial vehicle, which was created using the CATIA V6 platform. COMSOL 5.6 software is used for structural and CFD analysis.

Computational Fluid Dynamic Analysis of the Flow Around a Propeller Blade of Multirotor Unmanned Aerodynamic Vehicle

Multirotor Unmanned Aerodynamic Vehicles (MUAV) have been a high interest topic in the aerodynamic community for its many applications, such as, logistics, emergency rescue, agriculture data collection, and environmental sensing to name a few. MUAV propeller blades create a highly complex turbulent fluid flow around the body and the environment around it. The flow physics generated from the rotation of the propeller blades were studied in this paper along with the analysis of aerodynamic characteristics. A Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) analysis of a propellor blade from a MUAV has been performed to quantify the aerodynamic effects. For this purpose, the verification and validation of the commercially available CFD solver COMSOL Multiphysics v5.5 was performed using the NACA 0012 airfoil which is one of the most highly studied of the NACA family. With this validation it created confidence on the results for simulating a MUAV propeller and evaluate the aerodynamic characteristics of thrust coefficient (KT), power coefficient (KP), and Efficiency (η). These characteristics were compared against experimental data and results showed to have a similar trend. This showed that the CFD solver is capable of solving the aerodynamic characteristics of any propeller blade geometry.

Computational Fluid Dynamic Analysis Supports the Hemodynamic Stability of Hybrid Combinations With the AFX Bifurcate and Nitinol-Based Proximal Segments in Solutions of Failed Endovascular Aneurysm Repair

Hybrid endograft combinations of two or more different types of covered stents are rarely reported to treat complex abdominal aortic aneurysm cases or primary and secondary endoleaks. Clinical and laboratory data regarding the clinical efficacy and mechanical stability of such combinations are lacking. Based on a recently published case report, we describe and comment on the hemodynamic profile of a representative simulated hybrid case of AFX and Nitinol-based proximal cuff and support the stability of this combination in non-angulated cases.

Optimal Air Conditioner Placement Using a Simple Thermal Environment Analysis Method for Continuous Large Spaces with Predominant Advection

The number of houses with large, continuous spaces has increased recently. With improvements in insulation performance, it has become possible to efficiently air condition such spaces using a single air conditioner. However, the air conditioning efficiency depends on the placement of the air conditioner. The only way to determine the optimal placement of such air conditioners is to conduct an experiment or use computational fluid dynamic analysis. However, because the analysis is performed over a limited period, it is difficult to consider non-stationarity effects without using an energy simulation. Therefore, in this study, energy simulations and computational fluid dynamics analyses were coupled to develop a thermal environment analysis method that considers non-stationarity effects, and various air conditioner arrangements were investigated to demonstrate the applicability of the proposed method. The accuracy verification results generally followed the experimental results. A case study was conducted using the calculated boundary conditions, and the results showed that the placement of two air conditioners in the target experimental house could provide sufficient air conditioning during both winter and summer. Our results suggest that this method can be used to conduct preliminary studies if the necessary data are available during design or if an experimental house is used.