CFD Analysis of a Single-Stage Suborbital Rocket Christopher Simpson & Dr. Charles O’Neill The University of Alabama

Overview Scope and Objectives Stability: An Overview Computational Fluid Dynamics 6 Degree of Freedom Solver Results, Discussion, & Future Work Q&A

Research Scope and Objectives

Scope of the Project Rocket Design Model Single-stage Suborbital No Controls Computational Scope Max speed: M=0.6 Interpolation of data from FUN3D 6DOF tracks flight path 6DOF gives stability derivatives Objectives Stability CFD 6DOF Application

Objectives Realistic Modeling CFD provides accurate prediction of aerodynamic forces Can introduce multiple, “What if,” scenarios Stability and Controls Output stability margins Build a base model Controls will be introduced later Rapid Prototyping Objectives Stability CFD 6DOF Application

Stability: An Overview

Stability: xcp , xnp , and Derivatives Examination of a single-stage suborbital hobby rocket with an L-class motor Tracking xcp and xnp over the simulated flight of the rocket Easy extraction of stability derivatives Objectives Stability CFD 6DOF Application

Stability Derivatives Objectives Stability CFD 6DOF Application

Computational Fluid Dynamics

Rigid Body Model Objectives Stability CFD 6DOF Application

Mesh Objectives Stability CFD 6DOF Application

Pointwise: Mesh Creation NASA Geolab’s worksheet for estimating normal spacing to be used in a viscous CFD grid was consulted: ds = 6.92E-05, found using Re for max velocity Estimates the spacing normal to a solid surface required to yield 1 grid point in the laminar sublayer Objectives Stability CFD 6DOF Application

FUN3D (CFD) Objectives Stability CFD 6DOF Application

6 Degree of Freedom (6DOF) Solver Christopher Simpson The University of Alabama

6 Degree of Freedom Solver 6DOF uses a 13 state variable equation to solve for the system through numerical integration Quaternions are used to update the orientation from the body axis to the inertial frame Objectives Stability CFD 6DOF Application

6 Degree of Freedom Solver The non-inertial formulation of the 6DOF rigid body dynamics solver allows for an intuitive and simple stability derivative extraction routine The stability derivatives allow NP and CP to be tracked as the apparent AOA changes Objectives Stability CFD 6DOF Application

Cx CZ Objectives Stability CFD 6DOF Application

CMx CMy Objectives Stability CFD 6DOF Application

Results, Discussion, & Future Work

Results & Discussion Objectives Stability CFD 6DOF Application

Results & Discussion Up to 20.5 lbs. could be added at the aft of the vehicle Correct estimates are critical to design Objectives Stability CFD 6DOF Application

Future Work Conversion of code from interpreted to compiled code Introduction of controls into the system Further CFD analysis of the rocket body Linearized expressions to optimize design before CFD work Objectives Stability CFD 6DOF Application

Christopher Simpson The University of Alabama Q&A? Christopher Simpson The University of Alabama

Alabama Rocket Engineering Systems Rocket Launch Objectives Stability CFD 6DOF Application