AeroRocket Engineering

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Providing Affordable Aerodynamics Software Since November 1, 1999

AeroCFD®

CFD Analysis of a sphere-cone-cylinder rocket at Mach 3 and 0.0 degrees angle of attack. Vehicle shape developed using a CAD generated Sphere-Cone-Cylinder text format geometry file. This CFD analysis required only 10 minutes to generate the specified airframe geometry and supersonic mesh to achieve convergence in 500 iterations. Run time was about 20 minutes.
 

AeroCFD successfully determined drag coefficient (Cd) verses Mach number from Mach 0.5 to Mach 5.0 for the full scale V-2 rocket operating at 4 degrees angle of attack. AeroCFD predicts Cd = 0.279 at Mn = 2 and AOA = 4 degrees.

A
eroCFD
is a "true" 3-D axisymmetric and 2-D implicit finite volume CFD program that solves the inviscid Euler equations for subsonic, transonic and supersonic flow to Mach 7 using automatic mesh generation and graphical results visualization. AeroCFD provides a maximum of 100 cells in the axial direction, 50 cells in the transverse direction and 10 cells in the circumferential (3-D) or thickness (2-D) direction. The outer boundary of the computational region is specified as the far-field, meaning captured shock waves pass through and are not reflected back into the computational volume. The latest version of AeroCFD has increased the number of discrete finite-volumes available for analysis from 18,000 cells to 50,000 cells. Due to its "true" 3-dimensional formulation, AeroCFD provides non-zero lift and non-zero pitching moment for axisymmetric shapes at angle of attack without requiring computational times exceeding one hour. Model geometry is specified by selecting from a library of standard shapes. Nose sections are defined using one of five basic shapes that include Conical, Ogive, Elliptical, Parabolic and Sears-Haack with power series coefficient. The user has the option for adding up to two constant diameter sections, one variable diameter transition section and one variable diameter boat tail section to complete the library of user-defined shapes. For added flexibility AeroCFD can import up to 1,000 X-R data points for generating axisymmetric and two-dimensional designs that require grid clustering in regions where shock waves and base flow dominate. Base flow aerodynamics are estimated using wind tunnel generated equations as a function of free stream Mach number and boat tail dimensions for subsonic and supersonic flow. The RESULTS section clearly displays FX, FY, MZ, CX, CY, CM, CD, CL, base drag, surface friction drag and center of pressure location. Flow fields are displayed using fill-contour plots, line-contour plots and surface distribution plots for pressure coefficient, pressure ratio, temperature ratio, density ratio and Mach number.

AeroCFD allows the user to control the mesh distribution around a body using simple point-and-click operations and are explained in simple step-by-step operating instructions. Model geometry is easily defined by selecting from a number of standard shapes that are automatically combined into one final shape with fins. In addition, transition shapes have a power series shape control for defining very unusual three-dimensional axisymmetric and 2-D shapes. In addition, the Fin Geometry utility allows the user to attach complex fins having several definition points to the final CFD airframe. Fin effects are superimposed on the final CFD solution using classical mechanics that are not part of the mesh definition. Using this methodology relatively thick fins having complex geometry are modeled efficiently for subsonic, supersonic and hypersonic flow to Mach 7.

AeroCFD uses a very efficient 3-D numerical analysis technique to solve the Euler equations for 1st, 2nd or 3rd order accuracy. An implicit finite volume numerical scheme uses upwind differencing methods that are biased in the direction determined by the signs of the characteristic speeds. Specifically, Steger-Warming flux-vector-splitting and Roe flux-difference-splitting methods are used for accurate solutions in shock-wave dominated flows. Shock waves are captured in as few as zero to one cell using the Roe flux-difference splitting methods. Subsonic flows use standard finite volume differencing methods. Engineering solutions are achieved in approximately 5 to 10 minutes using the default numerical settings for most models after a "good" mesh is developed.

Final Note: AeroCFD uses the compressible Euler equations for the aerodynamic analysis of high-speed rockets for flights greater than 0.3 Mach. The compressible Euler equations are derived from the full compressible Navier Stokes equations minus viscosity terms. Tremendous increase in solution efficiency and therefore computational speed are realized because for high-speed flight when Reynolds number is high (on the order of 10 million) the viscous forces are low and the boundary layer is thin indicating the flow is essentially inviscid. The Euler equations are preferred when modeling high-speed flight of aerospace vehicles even high-speed model and high power rockets. Conversely, low Reynolds number flight (on the order of 1 hundred) indicate viscous forces must be considered because the boundary layer is thick and probably laminar and not turbulent. Where, Reynolds number (Re = V L/v) is the ratio of inertial forces to viscous forces.

AeroCFD is a registered trademark owned by John Cipolla used to promote sales of his 3-D axisymmetric and 2-D Computational Fluid Dynamics (CFD) software and other related aerodynamics computer programs.

Featured AeroRocket CFD Codes
N
ozzle 10:
Compressible Flow Analysis of Converging-Diverging Nozzles GO
HyperCFD 10: Design of Supersonic and Hypersonic Re-entry and Rocket Vehicles GO

Latest Publications
Warp Drive Propulsion Using Magnetic Fields to
Distort Space-Time OR
First Successful Warp Drive Flight (2024)

Three-Stage Rocket Equation Analysis of the Saturn V Launch Vehicle
Excel Spreadsheet Multi-Stage Rocket Analysis, Technical Note 2023-1


FinSim Rocket Equation Burnout Velocity Accuracy Compared to
Finite Difference and TR-10 Prediction,
viXra e-print archive (2022)

Ring Fin Rocket Center of Pressure, Drag and Lift Slope Coefficients
Measured Using the AeroRocket Wind Tunnel, Technical Note 2022-2


Spool Rocket Center of Pressure and Drag Coefficient Measured
Using the AeroRocket Wind Tunnel, Technical Note 2022-1 (2022)

POF 291 Flutter Velocity Error Produces Negative Margins of
Safety Compared to NACA TN 4197, Technical Note 2021-2

FinSim 10 Torsional Stiffness of Rocket Fins
Thickness-Tapered From Root to Tip, Technical Note 2021-1


"Proving Shock Thickness Decreases for Increasing
Mach Number", Shock Wave Thickness Analysis (2020)


"Demonstrating the Relationship Between Quantum
Mechanics and Relativity", viXra e-print archive (2019)

"Computational and Experimental Interferometric Analysis
of a Cone-Cylinder-Flare Body"
(1989, 2015) viXra e-print archive

"Rocket Spin Stabilization Using Canted Fins", SpinSim (2002)
MathCAD document in this TN is copyright and requires permission to use


Author's viXra
e-print archive
Warp Drive Research
UFO investigation
Contact
AeroRocket


ALL SOFTWARE DISTRIBUTION HALTED AND PROGRAM DESCRIPTIONS REMOVED