Form 9.B Project Summary

Chron:

971574

Proposal

Number:

06.04-4800

Project Title:

A First-Principles Based High Order

Discontinuous Galerkin Methodology

for Rotorcraft Flowfield Studies

Technical Abstract (Limit 200 words)

A first-principles based high order Discontinuous

Galerkin (DG) methodology for rotorcraft flow field

studies is proposed. A 3rd/5th spatial order compact

DG methodology will be developed. The scheme

developed will be compact, i.e., the cell update

overtime depends only on the information from the

cell and its immediate neighbors. A unique

advantage of the compactness of this method is that

it does not require any special treatment near

boundaries and Chimera intergrid boundaries to

maintain high order accuracy.

The compact DG scheme will be implemented in

conjunction with an innovative selective overset

refinement method. This will ensure that the

rotor-blade tip vortices convect over large

distances without dissipation. Thus, this

methodology strives to achieve the philosophy of

h-p refinement for optimal computational efficiency

in the most practical manner. The compact high

order DG/selective overset refinement will be

implemented in an ENO-based high order 3D,

unsteady, overset NS solver specifically developed

for rotorcraft studies by the Principal Investigator

and the Consultant at Georgia Tech during the

demonstration phase.

The proposed methodology will be validated and

tip-vortex core velocity profiles will be compared

with experiments for a rotor in hover. The

comparative costs (CPU, memory overhead),

robustness of the proposed high order compact DG

method with conventional wide-stencil ENO,

MUSCL schemes will be analyzed. Information

fidelity during intergrid flow-feature transfers in

overset grids will be examined.

In Phase II, the focus will be on porting this

methodology to standard NASA platforms such as

OVERFLOW, and their application to handle

complex issues such as rotor-blade interactional

noise issues, generic rotor craft interactional

problems, and tip shape acoustic characteristics

predictions.

Potential Commercial Applications (Limit 200 words)

The proposed first-principles based efficient

resolution of vorticity-laden flowfield will be

applicable to diverse application such as non-linear

lift systems, high lift systems, and vortex buffeting

in fighter planes. Commercial application to civil

aviations include studies of wing-trailing vortex

dynamics from large aircrafts such as 747's, and

prediction of the life-span of such vortices.

Name and Address of Principal Investigator (Name,

Organization Name, Mail Address, City/State/Zip)

Nathan Hariharan

CFD Research Corporation

215 Wynn Dr.

Huntsville , AL 35805

Name and Address of Offeror (Firm Name, Mail Address,

City/State/Zip)

Andrzej J. Przekwas

CFD Research Corporation

215 Wynn Dr.

Huntsville , AL 35805