scholarly journals Flow Behaviour Assessment of Smokey SAM Rocket Prototype

CFD letters ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 42-56
Author(s):  
Nur Azam Abdullah ◽  
Nor Izzuddin Ismail ◽  
Izham Izzati Ismail ◽  
Muhammad Hanafi Azami ◽  
Norhuda Hidayah Nordin ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Open Source Software ◽  
High Speed ◽  
Lift Coefficient ◽  
Weight Ratio ◽  
Flight Performance ◽  
Stable Mode ◽  
Computational Fluid Dynamics Cfd ◽  
Design Requirements ◽  
Modelling Process

This paper presents an aerodynamic assessment on the "Smokey Sam Prototype (TRL-6) Start (X)". Initially, the rocket prototype was designed using OpenRocket open source software, where all of the user's design requirements and objectives are considered. The TRL-6 Smokey Sam Star (X) is expected to fly within 400 m with the operating Mach 0.2, as comparable to US GTR-18A. This research evaluates the aerodynamics performance of the design Smokey Sam prototype rocket using a computational fluid dynamics (CFD) approach. For instance, the CFD study assessed the flight performance and stability once launched, such as lift coefficient, drag coefficient and pitching moment. This research employs K-omega (k-ω) model to express the turbulent properties of the flow. The actual pressure distribution was compared with the conventional rocket material's exact pressure distribution to inspect the best rocket material to sustain the best strength to weight ratio at high-speed trajectory operation. Several observations were made into the modelling process, such as surrounding velocity and pressure. It is found that the flight is in stable mode since the obtained pitching moments are almost zero at all assessed speeds.

Aerodynamics of a wing under figure-of-eight flapping motion: FSI simulations

2021 ◽  
pp. 1-25
Author(s):  
Y.-J. Chu ◽  
H.-L. Liew ◽  
P. Balan Ganesan
Keyword(s):  
Pitch Angle ◽  
Lift Coefficient ◽  
Von Mises Stress ◽  
Flight Performance ◽  
Cfd Simulations ◽  
Balsa Wood ◽  
Flapping Motion ◽  
Computational Fluid Dynamics Cfd ◽  
Spatial Size ◽  
Von Mises

Abstract This paper investigates the aerodynamics of a wing under figure-of-eight flapping motion based on Fluid–Structure Interaction (FSI) Computational Fluid Dynamics (CFD) simulations. The kinematic of a wing under figure-of-eight motion creates a condition with a variable angle-of-attack. The effect of using different angles of attack at an initial condition, namely initial pitch angles, for the wing and the spatial size of the figure-of-eight pattern, namely the input link angle, is investigated. The initial pitch angles input is varied from 0° to 330° in steps of 30°, and the input link angles used are 30°, 45°, and 60°. The Young’s modulus of the wing is 3.4 GPa spanwise, which is the elastic modulus of balsa wood material. In comparison with an initial pitch angle of 0°, the 90° initial pitch angle shows much better flight performance in terms of lift generated and stability. The results show that the maximum average lift coefficient of 0.393 occurs at the 90° initial pitch angle. The maximum lift-induced moment for the 90° initial pitch angle is only 5.55% of the maximum lift induced moment for the 0° initial pitch angle. A higher input link angle generates a greater lift force. The pressure distribution in the vicinity of the wing area and the von Mises stress of the wing are also presented.

scholarly journals Drag Reduction by Application of Aerodynamic Devices in a Race Car

2020 ◽  
Author(s):  
Devang S. Nath ◽  
Prashant Chandra Pujari ◽  
Amit Jain ◽  
Vikas Rastogi
Keyword(s):  
Drag Reduction ◽  
Drag Force ◽  
High Speed ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Fuel Prices ◽  
Race Car ◽  
High Speeds ◽  
Maximum Drag Reduction ◽  
Computational Fluid Dynamics Cfd

Abstract In this era of fast-depleting natural resources, the hike in fuel prices is ever-growing. With stringent norms over environmental policies, the automotive manufacturers are on a voyage to produce efficient vehicles with lower emissions. High-speed cars are at a stake to provide uncompromised performance but having strict rules over emissions drives the companies to approach through a different route to keep the demands of performance intact. One of the most sought-after ways is to improve the aerodynamics of the vehicles. Drag force is one of the major setbacks when it comes to achieving high speeds when the vehicle is in motion. This research aims to examine the effects of different add on devices on the vehicle to reduce drag and make the vehicle aerodynamically streamlined. A more streamlined vehicle will be able to achieve high speeds and consequently, the fuel economy is also improved. The three-dimensional car model is developed in SOLIDWORKS v17. Computational Fluid Dynamics (CFD) is performed to understand the effects of these add on devices. CFD is carried out in the ANSYSTM 17.0 Fluent module. Drag Coefficient (CD), Lift Coefficient (CL), Drag Force and Lift Force are calculated and compared in different cases. The result of the simulations were analyzed and it was observed that different devices posed several different functionalities, but maximum drag reduction was found in the case of GT with spoiler and diffuser with a maximum reduction of 16.53%.

scholarly journals Drag reduction by application of aerodynamic devices in a race car

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Devang S. Nath ◽  
Prashant Chandra Pujari ◽  
Amit Jain ◽  
Vikas Rastogi
Keyword(s):  
Drag Reduction ◽  
Drag Force ◽  
High Speed ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Fuel Prices ◽  
Race Car ◽  
High Speeds ◽  
Maximum Drag Reduction ◽  
Computational Fluid Dynamics Cfd

AbstractIn this era of fast-depleting natural resources, the hike in fuel prices is ever-growing. With stringent norms over environmental policies, the automotive manufacturers are on a voyage to produce efficient vehicles with lower emissions. High-speed cars are at a stake to provide uncompromised performance but having strict rules over emissions drives the companies to approach through a different route to keep the demands of performance intact. One of the most sought-after ways is to improve the aerodynamics of the vehicles. Drag force is one of the major setbacks when it comes to achieving high speeds when the vehicle is in motion. This research aims to examine the effects of different add on devices on the vehicle to reduce drag and make the vehicle aerodynamically streamlined. A more streamlined vehicle will be able to achieve high speeds and consequently, the fuel economy is also improved. The three-dimensional car model is developed in SOLIDWORKS v17. Computational Fluid Dynamics (CFD) is performed to understand the effects of these add on devices. CFD is carried out in the ANSYS™ 17.0 Fluent module. Drag Coefficient (CD), Lift Coefficient (CL), Drag Force and Lift Force are calculated and compared in different cases. The result of the simulations was analyzed and it was observed that different devices posed several different functionalities, but maximum drag reduction was found in the case of GT with spoiler and diffuser with a maximum reduction of 16.53%.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

scholarly journals Research on aerodynamic characteristics of two-stage axial micro air turbine spindle for small parts machining

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098437
Author(s):  
Liu Jiang ◽  
Guo Zhiping ◽  
Miao Shujing ◽  
He Xiangxin ◽  
Zhu Xinyu
Keyword(s):  
High Speed ◽  
Aerodynamic Characteristics ◽  
Maximum Efficiency ◽  
Two Stage ◽  
Output Torque ◽  
Air Turbine ◽  
Solid Foundation ◽  
Computational Fluid Dynamics Cfd ◽  
Micro Machine ◽  
Small Parts

In order to meet the requirements of output torque, efficiency and compact shape of micro-spindles for small parts machining, a two-stage axial micro air turbine spindle with an axial inlet and outlet is proposed. Based on the k-ω turbulence model of SST, the flow field and operation characteristics of the two-stage axial micro air turbine spindle were studied using computational fluid dynamics (CFD) combined with an experimental study. We obtained the air turbine spindle under different working conditions of the loss and torque characteristics. When the inlet pressure was 300 KPa, the output speed of the two-stage turbine was 100,000 rpm, 9% higher than that of a single-stage turbine output torque. The total torque reached 6.39 N·mm, and the maximum efficiency of the turbine and the spindle were 42.2% and 32.3%, respectively. Through the research on the innovative structure of the two-stage axial micro air turbine spindle, the overall performance of the principle prototype has been significantly improved and the problems of insufficient output torque and low working efficiency in high-speed micro-machining can be solved practically, which laid a solid foundation for improving the machining efficiency of small parts and reducing the size of micro machine tool.

scholarly journals Numerical Investigation on the Influence of the Streamlined Structures of the High-Speed Train’s Nose on Aerodynamic Performances

2021 ◽  
Vol 11 (2) ◽  
pp. 784
Author(s):  
Zhenxu Sun ◽  
Shuanbao Yao ◽  
Lianyi Wei ◽  
Yongfang Yao ◽  
Guowei Yang
Keyword(s):  
Drag Reduction ◽  
Pressure Distribution ◽  
Flow Separation ◽  
High Speed ◽  
Leeward Side ◽  
Detached Eddy Simulation ◽  
Side Force ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Asymmetrical Design

The structural design of the streamlined shape is the basis for high-speed train aerodynamic design. With use of the delayed detached-eddy simulation (DDES) method, the influence of four different structural types of the streamlined shape on aerodynamic performance and flow mechanism was investigated. These four designs were chosen elaborately, including a double-arch ellipsoid shape, a single-arch ellipsoid shape, a spindle shape with a front cowcatcher and a double-arch wide-flat shape. Two different running scenes, trains running in the open air or in crosswind conditions, were considered. Results reveal that when dealing with drag reduction of the whole train running in the open air, it needs to take into account how air resistance is distributed on both noses and then deal with them both rather than adjust only the head or the tail. An asymmetrical design is feasible with the head being a single-arch ellipsoid and the tail being a spindle with a front cowcatcher to achieve the minimum drag reduction. The single-arch ellipsoid design on both noses could aid in moderating the transverse amplitude of the side force on the tail resulting from the asymmetrical vortex structures in the flow field behind the tail. When crosswind is considered, the pressure distribution on the train surface becomes more disturbed, resulting in the increase of the side force and lift. The current study reveals that the double-arch wide-flat streamlined design helps to alleviate the side force and lift on both noses. The magnitude of side force on the head is 10 times as large as that on the tail while the lift on the head is slightly above that on the tail. Change of positions where flow separation takes place on the streamlined part is the main cause that leads to the opposite behaviors of pressure distribution on the head and on the tail. Under the influence of the ambient wind, flow separation occurs about distinct positions on the train surface and intricate vortices are generated at the leeward side, which add to the aerodynamic loads on the train in crosswind conditions. These results could help gain insight on choosing a most suitable streamlined shape under specific running conditions and acquiring a universal optimum nose shape as well.

Numerical Analysis of Elevator Piston Effect on Building Airflow for an Air-Conditioned High-Rise Building in Winter

2014 ◽  
Vol 1008-1009 ◽  
pp. 1068-1074 ◽  
Author(s):  
Yan Wang ◽  
Yan Ling Guan ◽  
Yuan Sheng Yin
Keyword(s):  
Pressure Distribution ◽  
Upward Movement ◽  
Piston Effect ◽  
Air Conditioning System ◽  
Security Issues ◽  
High Rise ◽  
Computational Fluid Dynamics Cfd ◽  
Elevator Door ◽  
Mesh Technique ◽  
Storey Building

A model of a 24-storey building (94.5m high) with air-conditioning system was developed to analyze the elevator piston effect on building airflow by dynamic mesh technique of computational fluid dynamics (CFD). The results of the pressure distribution and airflow paths show that with the upward movement of elevator cabs, due to the elevator piston effect, changes in the pressure distribution and airflow paths occur in all the building; the pressure difference across the elevator door is enlarged, which is likely to cause some security issues; but the air exfiltration rate is hardly affected.

A Verification and Validation Study of CFD Simulation of Wind-Induced Ventilation on Building with Single-Sided Opening

2014 ◽  
Vol 554 ◽  
pp. 696-700 ◽  
Author(s):  
Nur Farhana Mohamad Kasim ◽  
Sheikh Ahmad Zaki ◽  
Mohamed Sukri Mat Ali ◽  
Ahmad Faiz Mohammad ◽  
Azli Abd Razak
Keyword(s):  
Open Source Software ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Previous Experiment ◽  
Experimental Methods ◽  
Verification And Validation ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Computational Fluid Dynamics Cfd ◽  
Model Approach

Wind-induced ventilation is widely acknowledged as one of the best approaches for inducing natural ventilation. Computational fluid dynamics (CFD) technique is gaining popularity among researchers as an alternative for experimental methods to investigate the behavior of wind-driven ventilation in building. In this present paper, Reynolds averaged Navier-Stokes equation (RANS) k-ε model approach is considered to simulate the airflow on a simplified cubic building with an opening on a single façade. Preliminary simulation using models from previous experiment indicates the reliability of OpenFOAM, the open source software that will be used in this study. The results obtained in this study will better define options for our future study which aims to explore how different buildings arrays modify the airflow inside and around a naturally ventilated building.

scholarly journals Numerical and Experimental Investigation on Key Parameters of the Respimat® Spray Inhaler

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Yi Ge ◽  
Zhenbo Tong ◽  
Renjie Li ◽  
Fen Huang ◽  
Jiaqi Yu
Keyword(s):  
High Speed ◽  
Fine Particles ◽  
Geometric Parameters ◽  
Metered Dose Inhalers ◽  
Geometric Pattern ◽  
Long Duration ◽  
Metered Dose ◽  
New Type ◽  
Computational Fluid Dynamics Cfd ◽  
Spray Velocity

Respimat®Soft MistTM is a newly developed spray inhaler. Different from traditional nebulizers, metered-dose inhalers, and dry powder inhalers, this new type of inhaler can produce aerosols with long duration, relatively slow speed, and a high content of fine particles. Investigating the effect of the key geometric parameters of the device on the atomization is of great significance for generic product development and inhaler optimization. In this paper, a laser high-speed camera experimental platform is built, and important parameters such as the geometric pattern and particle size distribution of the Respimat®Soft MistTM are measured. Computational fluid dynamics (CFD) and the volume of fluid method coupled with the Shear Stress Transport (SST) k-ω turbulence model are applied to simulate the key geometric parameters of the device. The effects of geometric parameters on the spray velocity distribution and geometric pattern are obtained. The angle of flow collision, the sphere size of the central divider and the length and width of the flow channel show significant impacts on the spray atomization.

Gliding Flight of the White-Backed Vulture Gyps Africanus

1971 ◽  
Vol 55 (1) ◽  
pp. 13-38 ◽  
Author(s):  
C. J. PENNYCUICK
Keyword(s):  
High Speed ◽  
Lift Coefficient ◽  
The Body ◽  
East African ◽  
Induced Drag ◽  
Gliding Flight ◽  
Vertical Speed ◽  
Statistical Sense ◽  
Pass Through ◽  
Comparison Measurements

1. Glide-comparison measurements were made on ten species of East African soaring birds using a Schleicher ASK-14 powered sailplane. Horizontal and vertical speed differences between bird and glider were measured by a photographic method, and used to estimate the bird's horizontal and vertical speeds relative to the air. The analysis refers to the white-backed vulture, since by far the largest number of measurements was obtained on this species. 2. A regression analysis using a two-term approximation to the glide polar yielded an implausibly high estimate of induced drag, which was attributed to a lack of observations at lift coefficients above 0.72. An amended glide polar was constructed assuming elliptical lift distribution and a maximum lift coefficient of 1.6 to define the low-speed end, while the high-speed end was made to pass through the mean horizontal and sinking speeds of all the experimental points. This curve gave a minimum sinking speed of 0.76 m/s at a forward speed of 10 m/s, and a best glide ratio of 15.3:1 at 13 m/s. It did not differ significantly (in the statistical sense) from the original regression curve. 3. In comparing the estimated circling performance, based on the amended glide polar, with that of the ASK-14, it was concluded that the rates of sink of both should be comparable, but that the glider would require thermals with radii about 4.3 times as great as those needed to sustain the birds. The conclusions are consistent with experience of soaring in company with birds. 4. In an attempt to assess the adaptive significance of the low-aspect-ratio wings of birds specializing in thermal soaring, the white-backed vulture's circling performance was compared with that of an ‘albatross-shaped vulture’, an imaginary creature having the same mass as a white-backed vulture, combined with the body proportions of a wandering albatross. It appears that the real white-back would be at an advantage when trying to remain airborne in thermals with radii between 14 and 17 m, but that the albatross-shaped vulture would climb faster in all wider thermals; on account of its much better maximum glide ratio, it should also achieve higher cross-country speeds. It is concluded that the wing shape seen in vultures and storks is not an adaptation to thermal soaring as such, but is more probably a compromise dictated by take-off and landing requirements. 5. The doubts recently expressed by Tucker & Parrott (1970) about the results and conclusions of Raspet (1950a, b; 1960) are re-inforced by the present experience.

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