Numerical Analysis Of Aerodynamic Characteristics Research Articles

Optimizing Supersonic Rocket Efficiency: a Numerical Analysis of Aerodynamic Characteristics and Angle of Canard Deflection

Optimizing Supersonic Rocket Efficiency: a Numerical Analysis of Aerodynamic Characteristics and Angle of Canard Deflection

Numerical analysis of aerodynamic characteristics of multi-pod hyperloop system

The Hyperloop system is a new and innovative mode of transportation in which high-speed pods move through near-vacuum tubes. The multi-pod Hyperloop Systems are essential for increased transportation capacity. In this study, a multi-pod Hyperloop System was analyzed using numerical simulations at different values of the distance between the pods (i.e., 2 L–3.5 L). The pressure and velocity flow fields and the aerodynamic characteristics of the pods were analyzed for four different flow speeds, that is, 100, 200, 300, and 400 m/s, using unsteady compressible flow conditions. The simulation results indicated that the pressure waves generated across the pods play a significant role in the determination of the aerodynamic characteristics of the pods. Increasing the distance between the pods results in the delay of the pressure wave interaction. The aerodynamic drag increases on the first pod with the increase in the distance between the pods due to an increase in the pressure gradient. In contrast, the aerodynamic drag decreases across the second pod with the increase in the distance between them. So, the distance between the pods is a critical factor that should be considered when designing the Hyperloop System with more than one pod.

Numerical Aerodynamic Investigation of Exhaust Diffuser for Powerful Steam Turbine in a Wide Operating Modes Range

The objectives of research done were to define the aerodynamic characteristics of the different axial-radial diffusers constructions on load-changing turbine operations with the purpose to find their aerodynamic improvement reserve. Using the CFD program, the numerical analysis of aerodynamic characteristics has been performed for the four options of outlet axial-radial diffusers used for the steam turbine K-325-23,5. The flow for all four options of the diffuser was calculated for preset constant total pressure and total temperature at the channel input and the static pressure at the diffuser output. The data was taken from experiment that had been performed by department of turbine construction of NTU “KhPI”. A comparative analysis of the aerodynamic characteristics of the diffusers was performed and the values of the coefficients of total losses were defined. A version of the outlet axial-radial diffuser was suggested for the turbine that provides the lowest coefficient of total losses and better flow distribution through entire channel.

Numerical Analysis of Aerodynamic Characteristics of Exhaust Passage with Consideration of Wet Steam Effect in a Supercritical Steam Turbine

To investigate the aerodynamic performance of exhaust passage under multi-phase flow, an actual case is conducted in the low-pressure double exhaust passages of 600 MW steam turbine. Then, the flow field is compared and analyzed with and without the built-in extraction pipelines based on the Eulerian–Eulerian homogenous medium multiphase method. Results show that the upstream swirling flow and downstream mixed swirling flow are the main causes to induce the entropy-increase in the exhaust passage. Moreover, the flow loss and static-pressure recovery ability in the exhaust hood are greater than those in the condenser neck. Compared with the flow field without the steam extraction pipelines, the entropy-increase increases, the static pressure recovery coefficient decreases, and the spontaneous condensation rates of wet steam decrease in the downstream area of the pipelines. With the increase of steam turbine loads, an increment in entropy-increase in the exhaust passage is 0.98 J/(kg·K) lower than that without steam extraction pipelines. Moreover, the incrementing range of uniformity coefficient is increased from 14.5% to 40.9% at the condenser neck outlet. It can be concluded that the built-in exhaustion pipeline can improve the aerodynamic performance of exhaust passage and better reflect the real state of the flow field. These research results can serve as a reference for turbine passage design.

Numerical Analysis of Aerodynamic Characteristics of Hyperloop System

The Hyperloop system is a new concept that allows a train to travel through a near-vacuum tunnel at transonic speeds. Aerodynamic drag is one of the most important factors in analyzing such systems. The blockage ratio (BR), pod speed/length, tube pressure, and temperature affect the aerodynamic drag, but the specific relationships between the drag and these parameters have not yet been comprehensively examined. In this study, we investigated the flow phenomena of a Hyperloop system, focusing on the effects of changes in the above parameters. Two-dimensional axisymmetric simulations were performed in a large parameter space covering various BR values (0.25, 0.36), pod lengths (10.75–86 m), pod speeds (50–350 m/s), tube pressures (~100–1000 Pa), and tube temperatures (275–325 K). As BR increased, the pressure drag was significantly affected. This is because of the smaller critical Mach number for a larger BR. As the pod length increased, the total drag and pressure drag did not change significantly, but there was a considerable influence on the friction drag. As the pod speed increased, strong shock waves occurred near the end of the pod. At this point, the flows around the pod were severely choked at both BR values, and the ratio of the pressure drag to the total drag converged to its saturation level. At tube pressures above 500 Pa, the friction drag increased significantly under the rapidly increased turbulence intensity near the pod surface. High tube temperatures increase the speed of sound, and this reduces the Mach number for the same pod speed, consequently delaying the onset of choking and reducing the aerodynamic drag. The results presented in this study are applicable to the fundamental design of the proposed Hyperloop system.

Numerical Analysis of Aerodynamic Characteristics of Iced Rotor in Forward Flight

Based on a three-dimensional rotor icing model and the CLORNS code, aerodynamic characteristics of iced rotors in forward flight are calculated and analyzed. At first, ice accretion on the UH-1H rotor in hover and ice accretion on the spinning rotor blade rotor in forward flight are calculated. The results are used to validate the employed numerical simulation method through comparisons with experimental data. Then, the degradation of the aerodynamic characteristics of the iced SRB rotor is analyzed, and the variation of the pressure coefficients on the rotor blades is discussed in detail. Finally, parameters such as the icing time, the temperature, and the icing position are quantified, and conclusions are obtained. The influence of the ice accretion on the sectional aerodynamic characteristics increases along the spanwise direction, and deicing near the 0.7R blade section should be preferred at the beginning of the ice accretion. Finally, it is concluded that ice will not be removed in time if the deicer is activated based solely on the variation of the rotor aerodynamics.

Numerical analysis of aerodynamic characteristics of high-speed train with different train nose lengths

In this study, based on the SST κ-ω turbulent model, the IDDES method is used to simulate the unsteady aerodynamic performance of trains with respect to different lengths of the tapered nose of the train (8 m and 12 m). The numerical simulation used in this study is verified through wind tunnel tests. The effects of the length of the tapered nose of the train on the aerodynamic performance, such as the train forces, boundary layer, velocity distribution, pressure distribution, and flow structure around the train, are elucidated via comparing and analyzing the obtained results. The results indicate that the effect of the length of the tapered nose of the train on the drag force of the tail car and lift force of the head car is stronger than the effect on other cars, and the Cd value of the tail car decreases by 30.53% and the Cl value of the head car increases by 87.98%. Increase in the length of the tapered nose of the train decreases the fluctuation of the drag and lift forces of the train, especially the head car. It is also observed that the boundary layer thickness around the train is decreased with the increase in the length of the tapered nose of the train. Moreover, it is observed that vortex drag is the primary factor in the aerodynamic drag of the tail car and that vortex drag primarily depends on the length of the tapered nose of the train.

Two dimensional numerical analysis of aerodynamic characteristics for rotating cylinder on concentrated air flow

Over the years, many studies have demonstrated the feasibility of the Magnus effect on spinning cylinder to improve lift production, which can be much higher than the traditional airfoil shape. With this characteristic, spinning cylinder might be used as a lifting device for short take-off distance aircraft or unmanned aerial vehicle (UAV). Nonetheless, there is still a gap in research to explain the use of spinning cylinder as a good lifting device. Computational method is used for this study to analyse the Magnus effect, in which two-dimensional finite element numerical analysis method is applied using ANSYS FLUENT software to examine the coefficients of lift and drag, and to investigate the flow field around the rotating cylinder surface body. Cylinder size of 30mm is chosen and several configurations in steady and concentrated air flows have been evaluated. All in all, it can be concluded that, with the right configuration of the concentrated air flow setup, the rotating cylinder can be used as a lifting device for very short take-off since it can produce very high coefficient of lift (2.5 times higher) compared with steady air flow configuration.

Numerical Analysis of Aerodynamic Characteristics of F-16

Maneuvering of the fighter aerodynamic have certain requirements, this paper for needs of F-16 aircraft maneuvering, according to some existing fighter of the gas dynamic layout and parameters and establish more accurate fighter aerodynamic configuration, internal structure parameters and control input quantity. This paper also introduces the standard atmosphere model and the engine model, and analyzes the control characteristics of the aircraft by verifying the zero input response and channel coupling characteristics, and analyzes the performance of the model. This method can be applied to the performance analysis of other models.

火星飛行機翼型の空力特性の数値解析

火星飛行機翼型の空力特性の数値解析

Numerical Analysis of Aerodynamic Characteristics of the Finned Surfaces with Cross-inclined Fins

Numerical Analysis of Aerodynamic Characteristics of the Finned Surfaces with Cross-inclined Fins

Numerical Analysis of Aerodynamic Characteristics of a of High-Speed Car With Movable Bodywork Elements

Abstract This paper presents the results of numerical analysis of aerodynamic characteristics of a sports car equipped with movable aerodynamic elements. The effects of size, shape, position, angle of inclination of the moving flaps on the aerodynamic downforce and aerodynamic drag forces acting on the vehicle were investigated. The calculations were performed with the help of the ANSYS-Fluent CFD software. The transient flow of incompressible fluid around the car body with moving flaps, with modeled turbulence (model Spalart-Allmaras or SAS), was simulated. The paper presents examples of effective flap configuration, and the example of configuration which does not generate aerodynamic downforce. One compares the change in the forces generated at different angles of flap opening, pressure distribution, and visualization of streamlines around the body. There are shown the physical reasons for the observed abnormal characteristics of some flap configurations. The results of calculations are presented in the form of pressure contours, pathlines, and force changes in the function of the angle of flap rotation. There is also presented estimated practical suitability of particular flap configurations for controlling the high-speed car stability and performance.

Numerical analysis of aerodynamic characteristics for the design of a small ducted fan aircraft

This article presents a study on the flow field and aerodynamic characteristics of the propellers and rudders for the design of a small ducted fan aircraft. In the analysis, an equivalent actuation disk was created as a simplified model of the propellers. A momentum source is determined by equivalent actuation disk numerical simulation using ANSYS CFX software based on vortex theory. In addition, the momentum source distribution function for the equivalent actuation disk model is improved by using experimental data. The computational fluid dynamics method in the ANSYS CFX software is then used to simulate the flow field of the propellers slipstream and determine the key aerodynamic and design parameters for the built-up rudders of the aircraft. The improved equivalent actuation disk method is validated by using the mixing plane method and their results show a good comparison. The simulation and analysis results provide the basis for optimal design of the built-up rudder arrangement and layout for a small ducted fan aircraft.

Numerical study on the aerodynamic performance and safe running of high-speed trains in sandstorms

The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China. An Eulerian two-phase model in the computational fluid dynamic (CFD) software FLUENT, validated with published data, was used to solve the gas-solid multiphase flow of a sandstorm around a train. The train aerodynamic performance under different sandstorm levels and no sand conditions was then simulated. Results showed that in sandstorm weather, the drag, lift, side forces and overturning moment increase by variable degrees. Based on a numerical analysis of aerodynamic characteristics, an equation of train stability was also derived using the theory of moment balance from the view of dynamics. A recommended speed limit of a train under different sandstorm levels was calculated based on the stability analysis.