scholarly journals Исследование метода оптимизации формы тела для уменьшения силы аэродинамического сопротивления в потоке газа

2018 ◽  
Vol 44 (8) ◽  
pp. 29
Author(s):  
Н.Н. Чернов ◽  
А.В. Палий ◽  
А.В. Саенко ◽  
А.М. Маевский
Keyword(s):  
Drag Force ◽  
Body Shape ◽  
Aerodynamic Drag ◽  
The Body ◽  
Constant Density ◽  
Body Of Revolution ◽  
Ansys Fluent ◽  
Bodies Of Revolution ◽  
Geometrical Shapes ◽  
Fluent Software

AbstractAerodynamic flow past bodies of various geometrical shapes was studied, and the aerodynamic drag force was reduced through optimization of the body shape using a specially proposed method. The resulting drag force was compared to that for bodies formed by revolution of the profiles of well-known standard series. The study was performed using the Ansys Fluent software for isothermal laminar steady-state flows of incompressible fluid with constant density in a velocity range of 0–10 m/s. It is shown that the aerodynamic drag force for a body with the optimized shape is lower than analogous values for the bodies of revolution with Su-26 and NASA-0006 reference profiles. In comparison to the aerodynamic-drag-force level of 100% for the body of revolution with NASA-0006 profile, the drag force for Su-26 profile at airflow velocity of 10 m/s is 89.4%, while that for the proposed optimized body shape is 89.2%.

A System to Measure Turbulent Lengthscales on Submerged Bodies of Revolution

2017 ◽  
Author(s):  
Christopher J. Chesnakas ◽  
Daniel R. Cadel
Keyword(s):  
Laser Doppler Velocimetry ◽  
Arrival Time ◽  
Noise Removal ◽  
The Body ◽  
Doppler Velocimetry ◽  
Body Of Revolution ◽  
Sampled Data ◽  
Bodies Of Revolution ◽  
Submerged Body ◽  
Cross Correlations

A system has been developed to measure the turbulent lengthscales in the flow about a submerged body of revolution. The system consists of two Laser Doppler Velocimetry (LDV) probes mounted inside the body of revolution with the beams projected outside of the body through conformal windows. The measurement volumes of the two probes can be independently positioned within a plane perpendicular to the body axis. The probes are used to measure velocity time series at various spacings in the flow field. Auto- and cross-correlations are computed for each measurement pair, from which integral lengthscales are then found. Measurements are compared to canonical data from a turbulent free shear jet. In this paper, the system is described and its theory of operation detailed. Methods of computing the velocity correlations from the random-arrival-time LDV measurements are presented, and a new noise-removal scheme for non-uniformly sampled data is introduced. Six methods for calculating the integral lengthscale from autocorrelation data are reviewed, and the results discussed for the present jet data measured with LDV.

A Note on the Resistance of Bodies of Revolution and Ship Forms

1974 ◽  
Vol 18 (03) ◽  
pp. 153-168
Author(s):  
N. Matheson ◽  
P. N. Joubert
Keyword(s):  
Boundary Layer ◽  
Reasonable Agreement ◽  
The Body ◽  
Experimental Results ◽  
Body Of Revolution ◽  
Bodies Of Revolution ◽  
Boundary Layer Development ◽  
Layer Development

A simple so-called 'equivalent' body of revolution is proposed for reflex ship forms in an attempt to simplify calculation of the boundary layer over a ship's hull when there is no wavemaking. How­ever, exhaustive testing of one body of revolution did not produce a favorable comparison with re­sults for the corresponding reflex model. Gadd's recently proposed theory was used to calculate the boundary-layer development over the body of revolution. Reasonable agreement was obtained between the calculated and experimental results.

Estimating on-Board Power Generation by Solar Photo-Voltaic Array Integrated Lighter-Than-Air Platform Under Variable Pitching Conditions

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Kuntal Ghosh ◽  
Shriya Vijay Pawar ◽  
Ayan Kumar Banerjee ◽  
Anirban Guha ◽  
Siddhartha P. Duttagupta
Keyword(s):  
Power Generation ◽  
Ambient Air ◽  
The Body ◽  
Solar Pv ◽  
Solar Insolation ◽  
Analytical Methodology ◽  
Ansys Fluent ◽  
Daunting Task ◽  
Fluent Software ◽  
Sustainable Power

Abstract Sustainable power generation on solar photovoltaic (SPV) modules integrated lighter-than-air platforms (LTAPs) is a daunting task since they are exposed to variable environmental factors such as wind, ambient air pressure, and incident solar insolation. Among these factors, the wind plays a significant role in destabilizing the system from its equilibrium position and affects the power generation. In this paper, we proposed a methodology for estimating the dynamics of power generation due to the destabilized pitching under different wind vectors. An alternative to the conventional fluid–structure interaction, a semi-analytical methodology has been formulated, utilizing commercial ansys fluent software, to estimate the pitching characteristics of lighter-than-air platform (LTAP). This pitching characteristic has been mapped to the body inertial frame for investigating the incident solar insolation followed by determining the corresponding power generation. The consequences of the envelope contour function (ECF) are also incorporated while characterizing the power generation. Furthermore, this study also provides scope for the placement of the solar PV array on LTAP in order to minimize losses in generated onboard power under variable pitching conditions.

scholarly journals Analysis of the axisymmetrical ionized gas boundary layer adjacent to porous contour of the body of revolution

2016 ◽  
Vol 20 (2) ◽  
pp. 529-540
Author(s):  
Slobodan Savic ◽  
Branko Obrovic ◽  
Nebojsa Hristov
Keyword(s):  
Boundary Layer ◽  
Gas Flow ◽  
Mhd Flow ◽  
The Body ◽  
Generalized Solutions ◽  
Body Of Revolution ◽  
Ionized Gas ◽  
Bodies Of Revolution ◽  
Boundary Layer Equations ◽  
Longitudinal Coordinate

The ionized gas flow in the boundary layer on bodies of revolution with porous contour is studied in this paper. The gas electroconductivity is assumed to be a function of the longitudinal coordinate x. The problem is solved using Saljnikov's version of the general similarity method. This paper is an extension of Saljnikov?s generalized solutions and their application to a particular case of magnetohydrodynamic (MHD) flow. Generalized boundary layer equations have been numerically solved in a four-parametric localized approximation and characteristics of some physical quantities in the boundary layer has been studied.

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

2015 ◽  
Vol 62 (4) ◽  
pp. 451-476 ◽  
Author(s):  
Tomasz Janson ◽  
Janusz Piechna
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Transient Flow ◽  
Aerodynamic Drag ◽  
Position Angle ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Ansys Fluent ◽  
Drag Forces ◽  
And Performance

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.

scholarly journals Numerical calculations of the autorotating rotor under transient conditions

2021 ◽  
Vol 2130 (1) ◽  
pp. 012030
Author(s):  
Z Czyż ◽  
A Kazimierska ◽  
P Karpiński ◽  
K Skiba
Keyword(s):  
Lift Force ◽  
Aerodynamic Drag ◽  
Geometric Model ◽  
Rotor Blades ◽  
Flight Safety ◽  
Main Rotor ◽  
Ansys Fluent ◽  
Transient Conditions ◽  
Sst Model ◽  
Fluent Software

Abstract It is necessary to evaluate the performance of the main rotor in design stages of a rotorcraft to obtain the assumed lift force and low aerodynamic drag. This paper presents the CFD numerical analysis of the autorotating rotor under transient conditions. Auto-rotation is particularly important in the case of gyrocopters, while in the case of helicopters it is related to flight safety. The calculations allowed us to obtain aerodynamic forces and torque as a function of rotor azimuth for individual rotor blades. The analysis was performed for a rotor tilted by 15 degrees toward the airflow direction. A geometric model was created for the calculations and then a computational model was created in Ansys Fluent software. The k-ω SST model was adopted as the turbulence model which considers the turbulence kinetic energy and its unit dissipation. The obtained results are presented in a rotor and flow coordinate system.

scholarly journals Investigation of Drag and Lift Forces over the Profile of Car with Rearspoiler using CFD

2015 ◽  
Vol 1 (8) ◽  
pp. 331
Author(s):  
Naveen Kumar Velagapudi ◽  
Lalit Narayan K. ◽  
L. N. V. Narasimha Rao ◽  
Sri Ram Y.
Keyword(s):  
Drag Force ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Fuel Utilization ◽  
Ansys Fluent ◽  
Total Drag ◽  
Rear Spoiler ◽  
Computational Fluid Dynamics Cfd ◽  
Lift Forces ◽  
Drag And Lift

Now a days demand of a high speed car is increasing in which vehicle stability is of major concern. Forces like drag& lift,weight,side forces and thrust acts on a vehicle when moving on road which significantly effect the fuel consumption The drag force is produced by relative motion between air and vehicle and about 60% of total drag is produced at the rear end. Reduction of drag force at the rear end improves the fuel utilization. This work aims to reduce the drag force which improves fuel utilization and protects environment as well. In the stage of work a sedan car with different types of spoilers are used to reduce the aerodynamic drag force. The design of sedan car has been done on CATIA-2010 and the same is used for analysis in ANSYS-(fluent). The analysis is done for finding out drag and lift forces at different velocities, and spoilers. This study proposes an effective numerical model based on the computational fluid dynamics (CFD) approach to obtain the flow structure around a passenger car with a rear spoiler

An Inverse Method for the Design of Bodies of Revolution by Boundary Integral Modelling

1991 ◽  
Vol 205 (2) ◽  
pp. 91-97 ◽  
Author(s):  
R I Lewis
Keyword(s):  
Inverse Method ◽  
Body Shape ◽  
Axisymmetric Flow ◽  
Vortex Sheet ◽  
Boundary Integral ◽  
The Body ◽  
Boundary Integral Method ◽  
Bodies Of Revolution ◽  
Final Design ◽  
Induced Flow

A surface vorticity boundary integral method is presented for the design of bodies of revolution in axisymmetric flow. The analysis finds the desired body shape to deliver a prescribed surface potential flow velocity or pressure distribution. To achieve this the body surface is simulated by a flexible vorticity sheet of prescribed strength. Starting from an arbitrary first guess for the body shape, normally an ellipsoid, the flexible vortex sheet is successively realigned with its own self-induced flow field during an iterative process which converges accurately onto the desired shape. A well-proven analysis method is also presented for back-checking the final design.

A Method of Body Shape Optimization for Decreasing the Aerodynamic Drag Force in Gas Flow

2018 ◽  
Vol 44 (4) ◽  
pp. 328-330 ◽  
Author(s):  
N. N. Chernov ◽  
A. V. Palii ◽  
A. V. Saenko ◽  
A. M. Maevskii
Keyword(s):  
Shape Optimization ◽  
Drag Force ◽  
Gas Flow ◽  
Body Shape ◽  
Aerodynamic Drag

Turbulent Boundary Layers on Bodies of Revolution

1982 ◽  
Vol 26 (02) ◽  
pp. 135-147 ◽  
Author(s):  
A.J. Smits ◽  
P. N. Joubert
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layers ◽  
The Body ◽  
Two Dimensional ◽  
Body Of Revolution ◽  
Calculation Methods ◽  
Bodies Of Revolution ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow ◽  
Simple Summation

Turbulent boundary-layer flow over two arbitrary bodies of revolution was investigated by comparison with the flow over a two-dimensional wing-like body. For each body of revolution this wing" was first shaped to copy the body of revolution pressure distribution and then modified to have the same longitudinal curvature. The results were interpreted in terms of the effects of the extra rates of strain associated with longitudinal curvature and lateral divergence. These effects could be distinguished reasonably clearly and the experimental results should prove useful for testing calculation methods. Comparison with the calculations of Bradshaw et al [8, 9] shows that there occurs a strong interaction between the extra rates of strain due to convex curvature and divergence and that the implied simple summation of these two effects cannot be justified.

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