scholarly journals Numerical Calculation of Effect of Elastic Deformation on Aerodynamic Characteristics of a Rocket

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Laith K. Abbas ◽  
Dongyang Chen ◽  
Xiaoting Rui
Keyword(s):  
Lift Force ◽  
Normal Force ◽  
Center Of Pressure ◽  
Aerodynamic Characteristics ◽  
Force Distribution ◽  
Pitching Moment ◽  
Flight Trajectory ◽  
Aerodynamic Coefficients ◽  
Computational Fluid Dynamics Cfd ◽  
Drag And Lift

The application and workflow of Computational Fluid Dynamics (CFD)/Computational Structure Dynamics (CSD) on solving the static aeroelastic problem of a slender rocket are introduced. To predict static aeroelastic behavior accurately, two-way coupling and inertia relief methods are used to calculate the static deformations and aerodynamic characteristics of the deformed rocket. The aerodynamic coefficients of rigid rocket are computed firstly and compared with the experimental data, which verified the accuracy of CFD output. The results of the analysis for elastic rocket in the nonspinning and spinning states are compared with the rigid ones. The results highlight that the rocket deformation aspects are decided by the normal force distribution along the rocket length. Rocket deformation becomes larger with increasing the flight angle of attack. Drag and lift force coefficients decrease and pitching moment coefficients increase due to rocket deformations, center of pressure location forwards, and stability of the rockets decreases. Accordingly, the flight trajectory may be affected by the change of these aerodynamic coefficients and stability.

The Influence of Non-linear Longitudinal Aerodynamic Characteristics on the Power Spectral Response of Aircraft to Atmospheric Turbulence

1973 ◽  
Vol 24 (4) ◽  
pp. 284-294
Author(s):  
P A T Christopher ◽  
J M H Dunn
Keyword(s):  
Root Mean Square ◽  
Normal Force ◽  
Spectral Response ◽  
Aerodynamic Characteristics ◽  
Pitching Moment ◽  
Mean Square ◽  
Acceleration Response ◽  
Spectral Technique ◽  
Power Spectral ◽  
Normal Acceleration

SummaryThe power spectral technique has been extended to show the effect of aerodynamic non-linearities on the normal acceleration response of a rigid aircraft in the cruise configuration. Non-linearities in the normal force and pitching moment variations with incidence have been considered. The resulting changes from the linear root-mean-square values of normal acceleration were only 3 to 5½% for a root-mean-square vertical gust velocity of 20 m/s.

scholarly journals Calculation of aerodynamic characteristics of flying objects using Prodas and Fluent environments

Mechanik ◽  
2017 ◽  
Vol 90 (7) ◽  
pp. 591-593
Author(s):  
Leszek Baranowski ◽  
Michał Frant
Keyword(s):  
Mach Number ◽  
Experimental Method ◽  
Drag Force ◽  
Lift Force ◽  
Incidence Angle ◽  
Theoretical Method ◽  
Aerodynamic Characteristics ◽  
Pitching Moment ◽  
Force Coefficient ◽  
Moment Coefficient

The article presents the methodology of determining the basic aerodynamic characteristics using the Fluent theoretical method and the theoretical and experimental method using the Prodas program. Presented calculations were made for a 122 mm non-guided missile. In order to compare both methods, the results of calculations of coefficient of drag force, lift force coefficient and pitching moment coefficient as a function of incidence angle of attack and Mach number are shown in graphs.

scholarly journals Multiple Aerodynamic Coefficient Prediction of Airfoils Using a Convolutional Neural Network

Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 544
Author(s):  
Hai Chen ◽  
Lei He ◽  
Weiqi Qian ◽  
Song Wang
Keyword(s):  
Neural Network ◽  
Prediction Model ◽  
Convolutional Neural Network ◽  
Model Simulation ◽  
Prediction Method ◽  
Aircraft Design ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Coefficients ◽  
Pitch Moment ◽  
Drag And Lift

Both symmetric and asymmetric airfoils are widely used in aircraft design and manufacture, and they have different aerodynamic characteristics. In order to improve flight performance and ensure flight safety, the aerodynamic coefficients of these airfoils must be obtained. Various methods are used to generate aerodynamic coefficients. The prediction model is a promising method that can effectively reduce cost and time. In this paper, a graphical prediction method for multiple aerodynamic coefficients of airfoils based on a convolutional neural network (CNN) is proposed. First, a transformed airfoil image (TAI) was constructed by using the flow-condition convolution with the airfoil image. Next, TAI was combined with the original airfoil image to form a composite airfoil image (CAI) that is used as the input of the CNN prediction model. Then, the structure and parameters of the prediction model were designed according to CAI features. Finally, a sample set that was generated on the basis of the deformation of symmetrical airfoil NACA 0012 was used to train and test the prediction model. Simulation results showed that the proposed method based on CNN could simultaneously predict the pitch-moment, drag, and lift coefficients, and prediction accuracy was high.

scholarly journals NUMERICAL SIMULATION ON REAR SPOILER ANGLE OF MINI MPV CAR FOR CONDUCTING STABILITY AND SAFETY

SINERGI ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 23
Author(s):  
Alief Avicenna Luthfie ◽  
Dedik Romahadi ◽  
Hanif Ghufron ◽  
Solli Dwi Murtyas
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Drag Force ◽  
Lift Force ◽  
Lift Coefficient ◽  
Air Resistance ◽  
Rear Part ◽  
Rear Spoiler ◽  
Computational Fluid Dynamics Cfd ◽  
Drag And Lift

Spoiler attached on the rear part of a car can generate drag force and negative lift force, called downforce. This drag force can increase air resistance to the car, meanwhile, a negative lift force can improve the car’s stability and safety. Refer to many researchers, the shape and the angle of the spoiler give different aerodynamic effects and therefore give a different value of drag force and lift force. Based on these facts, this study was focused on the analysis of different spoiler angle attached to a mini MPV car to drag and lift force generated by the spoiler. The method used in this study is a numerical simulation using the Computational Fluid Dynamics (CFD) technique. The analysis was carried out at different spoiler angle and car’s speed. The spoiler angles are -20o, -10o, 0o, 10o, and 20o. The car’s speeds are 40 km/h, 60 km/h, 80 km/h, 100 km/h, and 120 km/h. Then the drag and lift force and their coefficient generated by different spoiler angles were being investigated at specified speeds. The result shows that higher spoiler angles generate higher drag and lower lift. Spoiler angles higher than 0o generate negative lift force, otherwise generate positive lift force. Therefore, to increase a car’s stability and safety, it is recommended to use a spoiler angle higher than 0o. Based on the result, it is best to use spoiler angle 10o because it generates negative lift force with -0.05 lift coefficient and 0,68 drag coefficient.

scholarly journals Effect of Gurney Flap Geometry on a S809 Airfoil

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Li-Shu Hao ◽  
Yong-Wei Gao
Keyword(s):  
Numerical Simulation ◽  
Lift Force ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Pitching Moment ◽  
Gurney Flaps ◽  
Gurney Flap ◽  
Linear And Nonlinear ◽  
Better Than

In this paper, the effect of Gurney flap shapes on wind turbine blade airfoil S809 has been studied by numerical simulation. First, the O-type grid is used in the numerical simulation. By comparing with experimental data, such as the lift force, the drag coefficient, and the pressure distribution, the accuracy of the simulation method is validated. Second, the research on the widths of three kinds of rectangular Gurney flaps at the trailing edge of the S809 airfoil is carried out. Rectangular Gurney flaps can considerably increase the lift in both the linear and nonlinear sections, and the maximum lift coefficient can be increased by 20.65%. In addition, the drag and the pitching moment are increased. However, the width of the rectangular Gurney flap has a small impact on the lift, the drag, and the pitching moment. Finally, the effects of rectangular and triangular Gurney flaps on the aerodynamic characteristics of the S809 airfoil are compared. The results show that the triangular flaps can obtain an increase of maximum lift coefficient by 28.42%, which is better than 16.31% of the rectangular flaps.

Experimental and Numerical Investigation of Automotive Aerodynamics Using DrivAer Model

2015 ◽  
Author(s):  
Lu Miao ◽  
Steffen Mack ◽  
Thomas Indinger
Keyword(s):  
Wind Tunnel ◽  
Numerical Investigation ◽  
Lift Force ◽  
Research Work ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
Navier Stokes ◽  
Basic Body ◽  
Limited Applicability ◽  
Drag And Lift

The use of experimental and numerical investigation to predict the aerodynamic characteristics of road vehicles is a standard practice in automotive design and development. Fundamental research has been often conducted on generic models with limited applicability to realistic cars. The DrivAer model developed in TU München possesses more representative car features. To encourage the use of the DrivAer model in independent research work, the experimental results and some numerical results were published. In this paper, a new developed wind tunnel setup of the DrivAer model was introduced. A new suspension system was designed in such a way that drag and lift force could be measured whilst the wheels are rolling on the moving ground without wheel struts (In this paper we call it wheels-on setup). The more close-truth experimental results of different rear end configurations were obtained. The lift force of the total model was firstly obtained. Additionally, the influences of the wheel struts and top sting were studied. Numerical investigation for performing finite-volume-based Reynolds-averaged Navier-Stokes (RANS) for the prediction of aerodynamic forces of passenger vehicles developed was presented, using the open-source CFD toolbox OpenFOAM®. Validation of the predictions was done on the basis of detailed comparisons to experimental wind tunnel data, both of the basic body (wheelhouse covered and without wheels) and the new wheels-on model. Results of drag coefficient were found to compare favourably to the experiments.

scholarly journals Аэродинамический профиль в трансзвуковом потоке газа

2021 ◽  
pp. 20-27
Author(s):  
Юрий Александрович Крашаница ◽  
Дмитрий Юрьевич Жиряков
Keyword(s):  
Numerical Methods ◽  
Transonic Flow ◽  
Center Of Pressure ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Pressure Coefficients ◽  
Standard Atmosphere ◽  
Drag And Lift ◽  
Cae System

The subject of investigation in this article is transonic flow. This is a condition in which local speeds of sound are appears on the wing surface, even at the subsonic speed of the nonturbulent flow. As a result, at a certain speed of the incoming flow, the flow regime around the aerodynamic surface will change sharply, which in turn changes the aerodynamic characteristics. Aerodynamic surfaces of the most transport category airplane experience transonic airflow during flight. The goal of the investigation is to study aerodynamic characteristics using numerical methods. The use of numerical methods in the design of aircraft structures is used more and more often to determine the optimal parameters for given operating conditions. This contributes to obtaining a more optimal and perfect design. In this article, we carried out a numerical analysis of the aerodynamic characteristics of airfoils in the transonic flow case using the CAE system CFD ANSYS. As a result of the research, the distributions of the pressure coefficients over the profile surface were obtained. The nature of the flow is obtained, which is similar to the picture of the pressure coefficients for transonic flow in the published sources of this topic. In the area of the middle of the profile, a shock-wave is observed. As a result, the flow around the airfoil changes, which contributes to a change in aerodynamic characteristics. The behavior of the aerodynamic drag and lift coefficients depending on the speed of the Mach number is considered. Also, the position of the center of pressure was analyzed at various velocities of the nonturbulent flow. The calculation was carried out at the cruising altitude of a medium-range aircraft of 11 km. For the calculations, we used the characteristics of the air temperature, the pressure of a given height from the table of the standard atmosphere.

Subsonic Wing-Body Interference for Missile Configurations at Large Angles of Attack

1977 ◽  
Vol 28 (3) ◽  
pp. 163-175 ◽  
Author(s):  
K D Thomson
Keyword(s):  
Normal Force ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Supporting Evidence ◽  
Pitching Moment ◽  
Aerodynamic Properties ◽  
Moment Estimates ◽  
Effective Angle ◽  
Series Of Experiments

SummaryAn approximate method is presented for estimating the normal-force and pitching-moment characteristics (including the effects of wing-body interference) of wings mounted on bodies. A pair of wings placed side by side can be specified which, when operating at a certain angle of attack different from the geometrical angle of attack, have the same aerodynamic properties as the wings in the presence of the body. The equivalent wings and effective angle of attack are determined, and these enable the wing-body normal force and pitching moment to be estimated for wing-body combinations at angles of attack up to 90°. Comparisons made with the results of a specially conducted series of experiments on rectangular and delta planform wing-body combinations have provided gratifying supporting evidence for the theory.Estimates are also made of the normal force and pitching moment produced by two cone-cylinder bodies over the angle of attack range 0° to 90°. These estimates, when added to the wing-body normal-force and pitching-moment estimates, have resulted in a set of longitudinal aerodynamic characteristics which are generally close to those found experimentally. The method appears to have application in the preliminary design phase for slewing missiles.

Aerodynamic Characteristics and Trajectory of Projectile with a Deflectable Nose

2014 ◽  
Vol 543-547 ◽  
pp. 16-19
Author(s):  
Ji Feng Wei ◽  
Xiong Li ◽  
Shu Shan Wang ◽  
Yu Xin Xu
Keyword(s):  
Experimental Data ◽  
Mach Number ◽  
Drag Coefficient ◽  
Aerodynamic Characteristics ◽  
Pitching Moment ◽  
Flight Trajectory ◽  
Start Time ◽  
Aerodynamic Efficiency ◽  
Moment Coefficient ◽  
Maximum Range

The basic experiment and detailed simulations are carried out to study the aerodynamic characteristics of projectile with deflectable nose. The parameters of computation are revised on the basis of experimental data. Further simulations show that the influence of mach number and deflectable angle on drag, lift, pitching moment and flight trajectory. The drag coefficient increases firstly and then decreases with the change of mach number, while drag coefficient and pitching moment coefficient grows exponentially. It can be seen that the ratio of lift to drag increases consistently, which means the aerodynamic efficiency of projectile would be improved with the increase of deflectable angle and mach number. The range is influenced by the start time of deflection. For the projectile with deflectable angle 10, the maximum range can be obtained if the forehead deflects at 3s.

Evaluation of Surface Finish Affect on Aerodynamic Coefficients of Wind Tunnel RP Models Production with ABSi Material

2008 ◽  
Vol 594 ◽  
pp. 255-260 ◽  
Author(s):  
A. Ahmadi Nadooshan ◽  
Saeed Daneshmand ◽  
C. Aghanajafi
Keyword(s):  
Wind Tunnel ◽  
Rapid Prototyping ◽  
Layer Thickness ◽  
Axial Force ◽  
Normal Force ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Testing ◽  
Aerodynamic Coefficients ◽  
Fused Deposition ◽  
Tunnel Testing

Nowadays, rapid prototyping (RP) methods are widely used to produce wind tunnel testing models and thickness of layers is an important parameter that affects the aerodynamic characteristics of model. This paper described the Affects layer thickness models product with rapid prototyping on Aerodynamic Coefficients for Constructed wind tunnel testing models. Three models were evaluated. These models were fabricated from ABSi by a fused deposition method (FDM). The layer thickness was 0.178mm, 0.254mm and 0.33mm. The roughness of surfaces for each model was 25/m, 63/m and 160/m (RZ) that determined by perthometer2. A wing-body-tail configuration was chosen for the actual study. Testing covered the Mach range of Mach 0.3 to Mach 1.2 at an angle-of-attack range of -4° to +16° at zero sideslip. Coefficients of normal force, axial force, pitching moment, and lift over drag are shown at each of these Mach numbers. Results from this study show that layer thickness does have an effect on the aerodynamic characteristics in general; the data differ between the three models by fewer than 6%. The layer thickness does have more effect on the aerodynamic characteristics when Mach number is decreased and had most effect on the aerodynamic characteristics of axial force and its derivative coefficients.

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