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A Multi-fidelity Computational Framework for Analyzing Flapping Flight
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Faculty,
Staff and Students: D.J.Willis, J. Peraire, M. Drela, P.-O. Persson, E.Israeli, A. Uranga
Collaborators:
K.S. Breuer, S.M. Swartz, D.H. Laidlaw (Brown University, RI), C. Moss (U. of Maryland), B.Batten (OSU) .
Understanding
the unsteady fluid structure interactions in flapping flight is
challenging and requires a multi-disciplinary approach involving
synergistic experiments (Brown University, U. of Maryland), theory (Brown
University/MIT/Oregon State University) and
computations(MIT/Oregon State University). In this Multidisciplinary University Research Initiative (MURI) between Brown
University, MIT, U. of Maryland, and Oregon State U., the research focus is to develop a deeper understanding of
bat flight (and more generally mammalian flight). Bat
flight presents significant challenges in all aspects of the project
ranging from low Reynolds number flight, experimental data collection in
unpredictable flight conditions to highly unsteady, large deformation (highly anisotropic materials),
fluid-structure interactions.
To achieve the
computational goals we are
implementing and using a multi-fidelity computational toolbox to model
the fluid dynamics and structural interactions in flapping flight. Due
to the multi-fidelity nature of the approach, the research questions
and objectives can be addressed using the
appropriate tool(s) at the appropriate level(s) of refinement. The
effective and efficient analysis of the research questions is strongly
related to the ability to answer the necessary questions at lower
fidelity levels, prior to increasing the cost of the computation
through higher fidelity analysis. For example,
when simple trend based trade-off analysis is desired, the use of a
high fidelity Navier Stokes fluid dynamics solver (3DG) is overkill
compared with a lower fidelity unsteady potential flow analysis
(FastAero, ASWING, or HallOpt); however, to examine the near wing flow
structures the high fidelity tool (3DG) is a good choice.
The
multi-fidelity framework is composed of the following tools:
- HallOpt: A wake only, minimum power tool based on the work of Hall et al. [1].
- ASWING: An unsteady, coupled lifting line - beam theory - control law model [2].
- FastAero: An unsteady, accelerated, high order panel method [3].
- 3DG: A high order Discontinuous Galerkin solver [4] (Navier Stokes, Non-Linear Structures, etc).
We are grateful for the support
of our sponsors, the AFOSR and the NSF [1]
Hall, K.C., Piggott, S.A., Hall, S.R., Power Requirements for Large
Amplitude Flapping Flight, Journal of Aircraft, Vol 35, # 3, 1998. [3] Willis,
D.J., Peraire, J. White, J.K., A combined pFFT-multipole
tree code, unsteady panel method with vortex particle wakes, 43rd AIAA
Aerospace Sciences
Meeting and Exhibit, AIAA 2005-0854, Reno, NV, Jan. 2005. [4] P.Persson and J.Peraire, An efficient low memory
implicit DG algorithm for time dependent problems' presented at 44th AIAA
Aerospace Sciences Meeting, AIAA-2006-0113, Reno, Nevada, 2006. questions:
djwillis(at)mit.edu
[2] Drela, M., Integrated Simulation Model for Preliminary Aerodynamic,
Structural, and Control-Law Design of Aircraft, AIAA 99-1394, 1999.