Presentation Title

Validating Aircraft Peformance using Computational Fluid Dynamics

Faculty Mentor

David Berger

Start Date

18-11-2017 10:00 AM

End Date

18-11-2017 11:00 AM

Location

BSC-Ursa Minor 91

Session

Poster 1

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

The Preliminary Research AerodyNamic Design to Land on Mars (PRANDTL-M) mission is to implement geometric twist in the wing design to produce a spanwise bell-shaped lift distribution and minimize induced drag for flight in the Martian atmosphere. A bell- shaped lift distribution drives the lift to zero at the wingtips, eliminating both the negative effects of wingtip vortices (adverse yaw) and the necessity of vertical stabilizers. To prove this concept and ensure its success, it is important to numerically evaluate the performance of the aircraft in its design stages and validate the results with flight data and other computational methods. Characterizing the performance of the PRANDTL-M aircraft involves conducting a computational fluid dynamics analysis on the airfoil geometry utilizing a two-dimensional method of airfoil analysis and a three-dimensional vortex lattice method. Airfoil coordinates are used as inputs to compute the aerodynamic coefficients. The changing shape of the PRANDTL-M airfoil along the wing requires that an integration method be used in conjunction with the two dimensional method of airfoil analysis in order to yield the total coefficients of lift, drag, and pitching moment. The results from the two and three dimensional analyses will be compared with each other and then validated with the aerodynamic coefficients that are computed from parameter identification test flight data.

Summary of research results to be presented

NASA AFRC began researching the bell-shaped spanload as the minimum drag solution for a wing with a given structure under the PRANDTL-D (Preliminary Research AerodyNamic Design To Lower Drag) project. A geometric twist in the wing produces the bell-shaped spanload and has been tested on multiple iterations of PRANDTL-D aircraft. It has also been applied to other propellers and small gliders. One such glider is the PRANDTL-M (Preliminary Research AerodyNamic Design To Land on Mars or PM).

Characterizing PM’s aircraft performance involves an analysis conducted on the airfoil geometry in computational fluid dynamics programs such as Eppler’s Profile and Lamar’s Vortex Lattice Method (VLM). The programs use airfoil coordinates as inputs to compute the aerodynamic coefficients of the glider. Results from Profile and VLM will be compared with each other and validated with aerodynamic coefficients computed from parameter identification test flight data.

Due to PM’s variable airfoil geometry from root to tip, a computational fluid analysis for each airfoil geometry at different stations is necessary to accurately characterize the aircraft in Profile. Additionally, a correction for the angle of attack is needed to account for wash and geometric twist. The total coefficients for the aircraft can be found by integrating the results along the wingspan. Results from the PRANDTL-M aircraft analysis in Profile can be compared with results from PID flight tests and other programs (such as VLM and Open VSP) to validate Profile’s analysis.

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Nov 18th, 10:00 AM Nov 18th, 11:00 AM

Validating Aircraft Peformance using Computational Fluid Dynamics

BSC-Ursa Minor 91

The Preliminary Research AerodyNamic Design to Land on Mars (PRANDTL-M) mission is to implement geometric twist in the wing design to produce a spanwise bell-shaped lift distribution and minimize induced drag for flight in the Martian atmosphere. A bell- shaped lift distribution drives the lift to zero at the wingtips, eliminating both the negative effects of wingtip vortices (adverse yaw) and the necessity of vertical stabilizers. To prove this concept and ensure its success, it is important to numerically evaluate the performance of the aircraft in its design stages and validate the results with flight data and other computational methods. Characterizing the performance of the PRANDTL-M aircraft involves conducting a computational fluid dynamics analysis on the airfoil geometry utilizing a two-dimensional method of airfoil analysis and a three-dimensional vortex lattice method. Airfoil coordinates are used as inputs to compute the aerodynamic coefficients. The changing shape of the PRANDTL-M airfoil along the wing requires that an integration method be used in conjunction with the two dimensional method of airfoil analysis in order to yield the total coefficients of lift, drag, and pitching moment. The results from the two and three dimensional analyses will be compared with each other and then validated with the aerodynamic coefficients that are computed from parameter identification test flight data.