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pimpleDymFOAM and NACA 23015 rotor

Posted July 29, 2015 at 08:58 by skeptik (CFD notes)

Not bad for the first time.
PolyDualMesh. 1,9M cells.

The comparation with CFX and Russian CFD package LOGOS from

Vladimirova, N.A., CFD ANALYSIS AND CALCULATION OF AERODYNAMIC CHARACTERISTICS OF HELICOPTER ROTOR, ERF 2013.

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Old

Introduction

Posted July 25, 2015 at 04:14 by LarryHowman

Hi, I've registered as a member to learn more about CFD and indirectly FEA and coding. I have some understanding, but am here as a student of engineering. All of my questions are innocent in origin, and are purely out of curiousity and of wanting to get a better grasp of something I find interesting.
My participation will be sporadic, as I have a young son who takes much of my 'free time', but as I'm doing this mainly for pleasure, there's no rush. I may be impatient at times, as I want to...
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Old

divDevRhoReff and divDevReff #2

Posted July 15, 2015 at 15:26 by Tobi

Incompressible
For incompressible fluids we again start with the viscous stress tensor \boldsymbol \tau:

\nabla \bullet \boldsymbol \tau = \nabla \bullet \left[-\frac{2}{3} \mu   \underline{\nabla \bullet   \textbf{U}}  \textbf{I} + \mu \nabla  \textbf{U} + \mu   (\nabla   \textbf{U})^T\right]

Hence, the density is constant the first term (underlined) at the RHS is zero due to the mass conservation equation:

\nabla\bullet \textbf{U}...
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Old

divDevRhoReff and divDevReff #1

Posted July 15, 2015 at 15:24 by Tobi

Hi all,

as I read befor, there are still some people available, who are confused about all that stuff. Therefore, I want to make the derivations and want to show you that the implementation is correct for both cases. We consider compressible and incompressible fluids. Further more I only take into account laminar flow and explain the way to get to divDevRhoReff and divDevReff.

Momentum equation

Lets start with the obvious momentum equation:

...
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Old

Impulse theory and small-scale blades

Posted May 26, 2015 at 07:37 by skeptik (CFD notes)

Very simple, very reliable impulse theory applied to small scale rotors, quad's alike, seems to be very promising.

Espesially at low velocities.

The data about propeller were obtained in thesis Isa Diana de Sousa Baptista Morais Carvalho "Low Reynolds Propellers for Increased Quadcopters Endurance",
the experimental data scrached from http://m-selig.ae.illinois.edu/props/propDB.html

Sure, it can be more precise but i've only used classical work...
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