Navier-Stokes Predictions of Aerodynamic Coefficients and Dynamic Derivatives of a 0.50-cal Projectile

2011 ◽  
Author(s):  
Sidra Silton
Keyword(s):  
Navier Stokes ◽  
Aerodynamic Coefficients ◽  
Derivatives Of

Longitudinal Aerodynamics of a Canard Guided Spin Stabilized Projectile

2012 ◽  
Vol 443-444 ◽  
pp. 719-723
Author(s):  
Xiu Ling Ji ◽  
Hai Peng Wang ◽  
Shi Ming Zeng ◽  
Chen Yang Jia
Keyword(s):  
Normal Force ◽  
Navier Stokes ◽  
Test Case ◽  
Aerodynamic Coefficients ◽  
Number Range ◽  
Detailed Understanding ◽  
Pitch Moment ◽  
Spinning Projectile ◽  
Mach 3 ◽  
Viable Approach

Navier–Stokes simulation is performed on a canard guided spinning projectile for different attack angles and circumferential position angles of canard over the Mach number range of 1.8–2.2. The computational Magnus moment coefficients of test case are validated with available experimental data of a Secant-Ogive-Cylinder-Boattail (SOCBT) configuration at Mach 3, demonstrating that the method can provide an accurate and viable approach for this problem. The aim of the present study is to provide a detailed understanding of the effects of canard with different circumferential position angles on longitudinal aerodynamic coefficients at three supersonic speeds and various angles of attack. And the results show that normal force coefficients and pitch moment coefficients vary periodically with the circumferential position angles of canard.

Database of Sail Shapes vs. Sail Performance and Validation of Numerical Calculation for Upwind Condition

2007 ◽  
Author(s):  
Yutaka Masuyama ◽  
Yusuke Tahara ◽  
Toichi Fukasawa ◽  
Naotoshi Maeda
Keyword(s):  
Numerical Method ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Numerical Calculations ◽  
Navier Stokes ◽  
Coupling Scheme ◽  
Aerodynamic Coefficients ◽  
Lattice Method ◽  
Cfd Method

Database of full-scale three-dimensional sail shapes are presented with the aerodynamic coefficients for the upwind condition of IMS type sails. Three-dimensional shape data are used for the input of numerical calculations and the results are compared with the measured sail performance. The sail shapes and performance are measured using a sail dynamometer boat Fujin. The Fujin is a 34-foot LOA boat, in which load cells and charge coupled devices (CCD) cameras are installed to measure the sail forces and shapes simultaneously. The sailing conditions of the boat, such as boat speed, heel angle, wind speed, wind angle, and so on, are also measured. The tested sail configurations are as follows: mainsail with 130% jib, mainsail with 75% jib and mainsail alone. Sail shapes are measured at several height positions. The measured shape parameters are chord length, maximum draft, maximum draft position, entry angle at the luff and exit angle at the leech. From these parameters three-dimensional coordinates of the sails are calculated by interpolation. These three-dimensional coordinates are tabulated with the aerodynamic coefficients. Numerical calculations are performed using the measured sail shapes. The calculation methods are of two types; Reynolds-averaged Navier-Stokes (RANS)-based CFD and vortex lattice methods (VLM). A multi-block RANS-based CFD method was developed by one of the authors and is capable of predicting viscous flows and aerodynamic forces for complicated sail configuration for upwind as well as downwind conditions. Important features of the numerical method are summarized as follows: a Finite- Analytic scheme to discretize transport equations, a PISO type velocity-pressure coupling scheme, multi-block domain decomposition capability, and several choices of turbulence models depending on flows of interest. An automatic grid generation scheme is also included. Another calculation method, the vortex lattice method is also adopted. In this case, step-by-step calculations are conducted to attain the steady state of the sail in steady wind. Wake vortices are generated step-by-step, which flow in the direction of the local velocity vector. These calculated sail forces are compared with the measured one, and the validity of the numerical method is studied. The sail shape database and comparison with numerical calculations will provide a good benchmark for the sail performance analysis of the upwind condition of IMS type sails.

Navier Stokes Derivative Estimates in Three Dimensions with Boundary Values and Body Forces

1991 ◽  
Vol 43 (6) ◽  
pp. 1161-1212 ◽  
Author(s):  
G. F. D. Duff
Keyword(s):  
Stokes Equations ◽  
Finite Energy ◽  
Three Dimensions ◽  
Navier Stokes ◽  
Boundary Values ◽  
Vector Solution ◽  
Navier Stokes Equations ◽  
Body Forces ◽  
Derivatives Of

AbstractFor a vector solution u(x, t) with finite energy of the Navier Stokes equations with body forces and boundary values on a region Ω ⊆ R3 for t > 0, conditions are established on the L6/5(Ω) and L2(Ω) norms of derivatives of the data that ensure the estimates and max , up to any given integer value of the weighted order 2r+s, where r or s = s1 + s2 + s3 > 0 and 0 < T < ∞.

Parametric Study of a Turbine Blade Cascade Using a New Parametric Flow Solver Turb’Opty

2002 ◽  
Author(s):  
S. Moreau ◽  
S. Aubert ◽  
M. N’Diaye ◽  
P. Ferrand ◽  
J. Tournier ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Stokes Equations ◽  
Taylor Series Expansion ◽  
Navier Stokes ◽  
Reference Solution ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Blade Cascade ◽  
Polynomial Reconstruction ◽  
Derivatives Of

A new parameterized CFD solver Turb’Opty™ has been developed based on a Taylor series expansion to high order derivatives of the solutions of the discretized Navier-Stokes equations. The method has been successfully applied to the laminar compressible flow field of the T106 turbine blade cascade. Comparisons with the classical CFD results have validated the accuracy of the parameterized solutions obtained by a simple polynomial reconstruction around a reference solution. The CPU efficiency has been emphasized by quickly computing the performance maps (power and losses) of this blade cascade. Wide industrial perspectives of turbomachinery global optimization are finally demonstrated by coupling this method with a simple genetic algorithm.

Aerodynamics analysis of the main rotor influence on the static stability of the gyroplane

2017 ◽  
Vol 89 (5) ◽  
pp. 663-670 ◽  
Author(s):  
Marcin Figat
Keyword(s):  
Dynamic Stability ◽  
Static Stability ◽  
Main Rotor ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Flight Condition ◽  
Configuration Change ◽  
Stability Derivatives ◽  
The Impact ◽  
Derivatives Of

Purpose This paper aims to present the results of aerodynamic calculation of impact the main rotor on the fuselage and the tail of a light gyroplane. This kind of vehicle is a type of rotorcraft which uses a non-powered rotor in autorotation to develop lift and engine-powered propeller to provide the thrust. Both of them disturb the flow around the gyroplane body (gyroplane fuselage and tail) and influence on its static stability. The main goal of the presented research was to find the magnitude of this influence. To measure this effect, the main stability derivatives changes of gyroplane body were investigated. Design/methodology/approach The CFD analysis of the complete gyroplane was made. Computation was performed for the model of gyroplane which was equipped with the two sub-models of the main rotor and the engine-powered propeller. Both of them were modelled as the actuator discs. This method allows to compute the aerodynamic impact of rotating components on the gyroplane body. All aerodynamic analysis was made by the MGAERO software. The numerical code of the software bases on the Euler flow model. Next, the resulting aerodynamic coefficients were used to calculate the most important stability derivatives of the gyroplane body. Findings The result obtained by computation presents the change in the most important aerodynamic coefficients and stability derivatives of the gyroplane body caused by the impact of its main rotor. Moreover, the result includes the change of the aerodynamic coefficients and stability derivatives caused by change of the main rotor configuration (change of rotation rate and angle of incidence) and change of the flight condition (gyroplane angle of attack sideslip angle and flight speed). Practical implications Analysis of the main rotor impact will be very useful for evaluation of dynamic stability of the light gyroplane. Moreover, the results will be helpful to design the horizontal and vertical tail for the light gyroplane. Originality/value This paper presents the method of the numerical analysis of the static stability of the light gyroplane’s body. The results of analysis present the impact of disturbance generated by the rotating main rotor on the static stability of the gyroplane body. Moreover, the impact of the main rotor configuration change and the flight condition change on the static stability were investigated too. The evaluation of the gyroplane’s body static stability was made by the stability derivatives. The methodology and obtained result will be very useful for analysis of the dynamic stability of the light gyroplanes. Moreover, the results will be helpful during design the main components of the gyroplane like vertical and horizontal tail.

scholarly journals Lower bound of decay rate for higher-order derivatives of solution to the compressible fluid models of Korteweg type

2020 ◽  
Vol 71 (4) ◽  
Author(s):  
Jincheng Gao ◽  
Zeyu Lyu ◽  
Zheng-an Yao
Keyword(s):  
Lower Bound ◽  
Decay Rate ◽  
Global Solution ◽  
Three Dimensional ◽  
Low Frequency ◽  
Navier Stokes ◽  
Whole Space ◽  
Spatial Derivatives ◽  
State 1 ◽  
Derivatives Of

Abstract This paper concerns the lower bound decay rate of global solution for compressible Navier–Stokes–Korteweg system in three-dimensional whole space under the $$H^{4}\times H^{3}$$ H 4 × H 3 framework. At first, the lower bound of decay rate for the global solution converging to constant equilibrium state (1, 0) in $$L^2$$ L 2 -norm is $$(1+t)^{-\frac{3}{4}}$$ ( 1 + t ) - 3 4 if the initial data satisfy some low-frequency assumption additionally. Furthermore, we also show that the lower bound of the $$k(k\in [1, 3])$$ k ( k ∈ [ 1 , 3 ] ) th-order spatial derivatives of solution converging to zero in $$L^2$$ L 2 -norm is $$(1+t)^{-\frac{3+2k}{4}}$$ ( 1 + t ) - 3 + 2 k 4 . Finally, it is proved that the lower bound of decay rate for the time derivatives of density and velocity converging to zero in $$L^2$$ L 2 -norm is $$(1+t)^{-\frac{5}{4}}$$ ( 1 + t ) - 5 4 .

scholarly journals External Aerodynamics Simulations in a Rotating Frame of Reference

2014 ◽  
Vol 2014 ◽  
pp. 1-14
Author(s):  
Filomena Cariglino ◽  
Nicola Ceresola ◽  
Renzo Arina
Keyword(s):  
Source Term ◽  
Computational Cost ◽  
Momentum Equation ◽  
Frame Of Reference ◽  
Navier Stokes ◽  
Rotating Frame ◽  
Stability Derivatives ◽  
Rotating Reference Frame ◽  
Naca 0012 ◽  
Derivatives Of

This paper presents the development of a tool integrated in the UNS3D code, proprietary of Alenia Aermacchi, for the simulation of external aerodynamic flow in a rotating reference frame, with the main objective of predicting propeller-aircraft integration effects. The equations in a rotating frame of reference have been formulated in terms of the absolute velocity components; in this way, the artificial dissipation needed for convergence is lessened, as the Coriolis source term is only introduced in the momentum equation. An Explicit Algebraic Reynolds Stress turbulence model is used. The first assessment of effectiveness of this method is made computing stability derivatives of a NACA 0012 airfoil. Finally, steady Navier-Stokes and Euler simulations of a four-blade single-rotating propeller are presented, demonstrating the efficiency of the chosen approach in terms of computational cost.

Extendable Chord Rotors for Helicopter Envelope Expansion and Performance Improvement

2014 ◽  
Vol 59 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Maryam Khoshlahjeh ◽  
Farhan Gandhi
Keyword(s):  
Performance Improvement ◽  
Dynamic Stall ◽  
Navier Stokes ◽  
Maximum Speed ◽  
Aerodynamic Coefficients ◽  
Trailing Edge ◽  
Low Altitude ◽  
And Performance ◽  
Analysis System ◽  
Chord Extension

This study explores the benefits of rotor chord extension in stall-dominant conditions. Simulations are based on a UH-60A Blackhawk helicopter with an effective chord increase of 20% realized by extending a trailing-edge plate (TEP) through a slit in the trailing edge between 63% and 83% blade span. Since TEP extension changes the baseline SC-1094R8 airfoil profile, two-dimensional aerodynamic coefficients of the modified profile from Navier–Stokes computational fluid dynamics calculations are used, coupled with 12 × 12 dynamic inflow and the Leishman–Beddoes dynamic stall model in the Rotorcraft Comprehensive Analysis System. While a fixed 20% larger chord produces comparable advantages to TEP extension in stall-dominant conditions, the rotor power requirements increase by up to nearly 4% for low gross weight, low-altitude operations, a penalty easily avoided with TEP retracted. From the simulations in the study, reductions of up to nearly 18% in rotor power requirements were observed with TEP for operation at high gross weight and altitude. Furthermore, increases of around 18 kt in maximum speed, 1500 lb in maximum gross weight capability, and 1800 ftin maximum altitude were observed. TEP extension generally reduces maximum angles of attack on the retreating side and weakens stall. Lift generally increases over the annulus where the TEP is present but reduces over the outer rim because the nose-down pitching moments produce larger nose-down elastic tip twist. With TEP extension, the offloading of the outer rim reduces drag, rotor torque, and power.

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