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Applebaum M.,Crm Solutions, Inc. | Eppard M.,Crm Solutions, Inc. | Hall L.,Crm Solutions, Inc. | Blevins J.,Crm Solutions, Inc. | Blevins J.,Marshall Space Flight Center
29th AIAA Applied Aerodynamics Conference 2011 | Year: 2011

This paper presents the methodology used to determine the protuberance aerodynamic loads for the NASA Ares I rocket program. The methodology presented utilizes computational fluid dynamics to obtain pressures and forces on the protuberances. The novelty of the current approach is the use of a discrete matrix of computational fluid dynamics simulations and the method in which the protuberance is decomposed to give the structural and venting engineer useful data. The methodology along with advantages and disadvantages to the current approach are discussed. Two examples of protuberances in the Ares I data book are given. © 2011 by the American Institute of Aeronautics and Astronautics, Inc.


Applebaum M.P.,Crm Solutions, Inc. | Hall L.H.,Crm Solutions, Inc. | Eppard W.M.,Crm Solutions, Inc. | Purinton D.C.,Gray Research Inc. | And 2 more authors.
53rd AIAA Aerospace Sciences Meeting | Year: 2015

This paper describes the development, testing, and utilization of an aerodynamic force and moment database for the Space Launch System (SLS) Service Module (SM) panel jettison event. The database is a combination of inviscid Computational Fluid Dynamic (CFD) data and MATLAB code written to query the data at input values of vehicle/SM panel parameters and return the aerodynamic force and moment coefficients of the panels as they are jettisoned from the vehicle. The database encompasses over 5000 CFD simulations with the panels either in the initial stages of separation where they are hinged to the vehicle, in close proximity to the vehicle, or far enough from the vehicle that body interference effects are neglected. A series of viscous CFD check cases were performed to assess the accuracy of the Euler solutions for this class of problem and good agreement was obtained. The ultimate goal of the panel jettison database was to create a tool that could be coupled with any 6-Degree-Of-Freedom (DOF) dynamics model to rapidly predict SM panel separation from the SLS vehicle in a quasi-unsteady manner. Results are presented for panel jettison simulations that utilize the database at various SLS flight conditions. These results compare favorably to an approach that directly couples a 6-DOF model with the Cart3D Euler flow solver and obtains solutions for the panels at exact locations. This paper demonstrates a method of using inviscid CFD simulations coupled with a 6-DOF model that provides adequate fidelity to capture the physics of this complex multiple moving-body panel separation event. © 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.


Hall R.A.,Crm Solutions, Inc. | Hough S.,NASA | Orphee C.,NASA | Clements K.,NASA
2016 AIAA Guidance, Navigation, and Control Conference | Year: 2016

Basic principles for the design and stability of a spacecraft on-orbit attitude control system employing on-off Reaction Control System (RCS) thrusters are presented. Both vehicle dynamics and the control system actuators are inherently nonlinear, hence traditional linear control system design approaches are not directly applicable. This paper has two main aspects: It summarizes key RCS design principles from earlier NASA vehicles, notably the Space Shuttle and Space Station programs, and introduces advances in the linear modelling and analyses of a phase plane control system derived in the initial development of the NASA’s next upper stage vehicle, the Exploration Upper Stage (EUS). Topics include thruster hardware specifications, phase plane design and stability, jet selection approaches, filter design metrics, and RCS rotational maneuver logic. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.


Applebaum M.,Crm Solutions, Inc. | Eppard M.,Crm Solutions, Inc. | Hall L.,Crm Solutions, Inc. | Blevins J.,NASA
Journal of Spacecraft and Rockets | Year: 2012

This paper presents the methodology used to determine the protuberance aerodynamic loads for NASA's Ares I Crew Launch Vehicle. The methodology presented used computational fluid dynamics to obtain pressures and forces on the protuberances. This is one of the first times computational fluid dynamics has been used to estimate protuberance aerodynamic loads for such a complicated configuration. The approach used a discrete matrix of computational fluid dynamics simulations and decomposed the protuberance in a manner suitable to give both the structural and venting engineers useful data. One of the guiding principles in the development of the data book was that the data book was to be used for analysis of protuberances and not in the design of the protuberance. In this regard, the data book contained significant conservatism both in the methodology and in the choice for a factor of conservatism. The methodology, along with advantages and disadvantages to the current approach, is discussed. Two examples of protuberances in the Ares I Aerodynamic Data Book are given. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.


Applebaum M.P.,Crm Solutions, Inc. | Eppard W.M.,Crm Solutions, Inc. | Hall L.,Crm Solutions, Inc.
Journal of Spacecraft and Rockets | Year: 2012

A number of Reynolds-averaged Navier-Stokes-based computational fluid dynamics solutions are presented that detail the effect of various thermochemical models on plume simulations. Four different levels of thermochemical models were considered, each with increasing complexity. In the simplest case, plumes were modeled with a single "perfect air" simulant gas that was calorically perfect. The second model used a single "equivalent" exhaust species that was calorically perfect but with molecular weight and frozen specific heats that mimicked the mass-averaged nozzle exit conditions. The third model used the same equivalent exhaust species but considered caloric imperfections. Finally, a full multispecies model with finite rate chemistry and general thermodynamics was considered. Comparisons are made between the different levels of modeling for power-on simulations involving the Ares I launch vehicle. The results show that, for simulations where plume impingement was very close to the exit of the nozzle or where insignificant plume impingement occurred, the perfect-air model performs well. For simulations in the vicinity of a cavity or where plume impingement occurred moderately downstream of the nozzle, the calorically imperfect equivalent model provides advantages over the other simplified thermodynamic models. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc.


Grant
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 124.99K | Year: 2012

In this SBIR CRM proposes to implement the entropy adjoint method for solution adaptive mesh refinement into the Loci/CHEM unstructured flow solver. The scheme will initially be developed and tested for ideal gases and will then be extended to encompass mixtures of thermally perfect/calorically imperfect gases. This approach will use the current remeshing algorithm in Loci/CHEM which utilizes nonstandard general polyhedral elements. The main objective is to provide a robust mesh adaptation scheme that will improve simulation accuracy while reducing overall computational costs. The principal incentive to NASA is to make large-scale, complex flow simulations more accurate and affordable so that their benefits can be fully realized within the design cycle. During Phase I we will perform mesh adaptations for a number of geometries and flow conditions of interest to NASA. We will use these simulations to evaluate the robustness and effectiveness of the new adaptation scheme to improve accuracy, and reduce overall computational cost.During Phase II we will implement a full adjoint scheme into Loci/CHEM. This is a natural extension of Phase I, and will not only allow for complete output-based mesh refinement capability, but will also allow Loci/CHEM to be used for uncertainty estimation and as a shape/geometry optimization tool. The combination of solution adaptive mesh refinement, shape optimization, and uncertainty estimation will provide NASA with a high-confidence, predictive tool for development and assessment of innovative aerodynamic concepts over a wide range of flight regimes.


Crm Solutions, Inc. | Entity website

CRM has extensive experience in computational modeling of core stage, stage separation and booster nozzle flow. Analysis efforts include:


Crm Solutions, Inc. | Entity website

CRM Solutions is a small business that provides full service engineering for launch vehicle, defense and aerospace needs. Founded in 1997, CRM Solutions is led by subject matter experts in all areas necessary for launch vehicle and defensive system engineering analyses ...


Crm Solutions, Inc. | Entity website

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Crm Solutions, Inc. | Entity website

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