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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Multifidelity Comparison Of Supersonic Wave Drag Prediction Methods Using Axisymmetric Bodies †, Troy Abraham, David Lazzara, Douglas Hunsaker
Multifidelity Comparison Of Supersonic Wave Drag Prediction Methods Using Axisymmetric Bodies †, Troy Abraham, David Lazzara, Douglas Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
Low-fidelity analytic and computational wave drag prediction methods assume linear aerodynamics and small perturbations to the flow. Hence, these methods are typically accurate for only very slender geometries. The present work assesses the accuracy of these methods relative to high-fidelity Euler, compressible computational-fluid-dynamics solutions for a set of axisymmetric geometries with varying radius-to-length ratios (R/L). Grid-resolution studies are included for all computational results to ensure grid-resolved results. Results show that the low-fidelity analytic and computational methods match the Euler CFD predictions to around a single drag count (~1.0 × 10–4) for geometries with R/L ≤ 0.05 …
Stick-Fixed Maneuver Points In Roll, Pitch, And Yaw And Associated Handling Qualities, Benjamin C. Moulton, Troy A. Abraham, Douglas F. Hunsaker
Stick-Fixed Maneuver Points In Roll, Pitch, And Yaw And Associated Handling Qualities, Benjamin C. Moulton, Troy A. Abraham, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
The stick-fixed pitch maneuver point is an important measure of aircraft longitudinal dynamic response and handling quality characteristics, and includes effects of both aerodynamic and inertia properties of the aircraft about the pitch axis. In the present work, the existence of stick-fixed roll and yaw maneuver points is demonstrated, which are determined from the lateral forces, moments, and inertial properties of the aircraft. These stick-fixed roll and yaw maneuver points are directly related to the predicted lateral handling qualities. Example results are included for several aircraft that demonstrate the importance of this parameter when predicting the dynamic response of the …
Evaluation Of First-Order Actuator Dynamics And Linear Controller For A Bio-Inspired Rotating Empennage Fighter Aircraft, Benjamin C. Moulton, Matthew W. Harris, Douglas F. Hunsaker, James J. Joo
Evaluation Of First-Order Actuator Dynamics And Linear Controller For A Bio-Inspired Rotating Empennage Fighter Aircraft, Benjamin C. Moulton, Matthew W. Harris, Douglas F. Hunsaker, James J. Joo
Mechanical and Aerospace Engineering Student Publications and Presentations
This paper considers the problem of stabilizing a bio-inspired fighter aircraft variant at its Air Combat Maneuver Condition. The aircraft equations of motion are linearized, and an infinite-horizon linear quadratic regulator design is conducted for this aircraft. Included in the dynamics are first-order actuator models, which have the effect of slowing actuator responses. This is particularly important for the bio-inspired variant because it requires rotation of the empennage, which has relatively large inertia. The bio-inspired variant open-loop system is unstable in the short period and Dutch roll modes, which is mitigated in the closed-loop system. Monte Carlo simulation responses to …
On The History And Semantics Of Burble In Aerodynamic Theory, Benjamin C. Moulton, Cory D. Goates, Troy A. Abraham
On The History And Semantics Of Burble In Aerodynamic Theory, Benjamin C. Moulton, Cory D. Goates, Troy A. Abraham
Mechanical and Aerospace Engineering Student Publications and Presentations
The term burble has been in use in aerodynamic theory for over a century. While burble may be unfamiliar to most contemporary aerodynamicists, the word has a rich history based in aerodynamic theory and experimentation. The present paper outlines the fluidity of burble's meaning over time. From analyzing subsonic flow over an airfoil, to the implementation of stochastic turbulence in aircraft carrier landing simulations, the term burble has had a significant impact on the study of aerodynamics. The term burble has fallen out of use in aerodynamic engineering circles. Why did this happen? And what can be learned from the …
An Alternate Dimensionless Form Of The Linearized Rigid-Body Aircraft Equations Of Motion With Emphasis On Dynamic Parameters, Douglas F. Hunsaker, Benjamin C. Moulton
An Alternate Dimensionless Form Of The Linearized Rigid-Body Aircraft Equations Of Motion With Emphasis On Dynamic Parameters, Douglas F. Hunsaker, Benjamin C. Moulton
Mechanical and Aerospace Engineering Student Publications and Presentations
The equations of motion for an aircraft can be linearized about a reference condition within the assumptions of small disturbances and linear aerodynamics. The resulting system of equations is typically solved to obtain the eigenvalues and eigenvectors that describe the small disturbance motion of the aircraft. Results from such an analysis are often used to predict the rigid-body dynamic modes of the aircraft and associated handling qualities. This process is typically carried out in dimensional form in most text books, or in nondimensional form using dimensionless parameters rooted in aerodynamic theory. Here we apply Buckingham’s Pi theorem to obtain nondimensional …
Simplified Mass And Inertial Estimates For Aircraft With Components Of Constant Density, Benjamin C. Moulton, Douglas F. Hunsaker
Simplified Mass And Inertial Estimates For Aircraft With Components Of Constant Density, Benjamin C. Moulton, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
Aircraft mass and inertial properties are required for predicting the dynamics and handling qualities of aircraft. However, such properties can be difficult to estimate since these depend on the external shape and internal structure, systems, and mass distributions within the airframe. Mass and inertial properties of aircraft are often predicted using computer-aided design software, or measured using various experimental techniques. The present paper presents a method for quickly predicting the mass and inertial properties of complete aircraft consisting of components of constant density. Although the assumption of constant density may appear limiting, the method presented in this paper can be …
Comparison Of Theoretical And Multi-Fidelity Optimum Aerostructural Solutions For Wing Design, Jeffrey D. Taylor, Douglas F. Hunsaker
Comparison Of Theoretical And Multi-Fidelity Optimum Aerostructural Solutions For Wing Design, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
As contemporary aerostructural research for aircraft design trends toward high-fidelity computational methods, aerostructural solutions based on theory are often neglected or forgotten. In fact, in many modern aerostructural wing optimization studies, the elliptic lift distribution is used as a benchmark in place of theoretical aerostructural solutions with more appropriate constraints. In this paper, we review several theoretical aerostructural solutions that could be used as benchmark cases for wing design studies, and we compare them to high-fidelity solutions with similar constraints. Solutions are presented for studies with 1) constraints related to the wing integrated bending moment, 2) constraints related to the …
Low-Fidelity Method For Rapid Aerostructural Optimisation And Design-Space Exploration Of Planar Wings, Jeffrey D. Taylor, Doug F. Hunsaker
Low-Fidelity Method For Rapid Aerostructural Optimisation And Design-Space Exploration Of Planar Wings, Jeffrey D. Taylor, Doug F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
During early phases of wing design, analytic and low-fidelity methods are often used to identify promising design concepts. In many cases, solutions obtained using these methods provide intuition about the design space that is not easily obtained using higher-fidelity methods. This is especially true for aerostructural design. However, many analytic and low-fidelity aerostructural solutions are limited in application to wings with specific planforms and weight distributions. Here, a numerical method for minimising induced drag with structural constraints is presented that uses approximations that apply to unswept planar wings with arbitrary planforms and weight distributions. The method is applied to the …
Characterization Of The Common Research Model Wing For Low-Fidelity Aerostructural Analysis, Jeffrey D. Taylor, Douglas F. Hunsaker
Characterization Of The Common Research Model Wing For Low-Fidelity Aerostructural Analysis, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
A characterization of the Common Research Model (CRM) wing for low-fidelity aerostructural optimization is presented. The geometric and structural properties are based on the CAD geometries and finite-element models for the CRM wing and the undeflected Common Research Model Wing (uCRM). Three approximations are presented for the elastic axis from previously-published studies on wing boxes similar to the uCRM, and approximations of the flexural and torsional rigidity are presented from a previously-published study using the uCRM wing. The characterization presented in this paper is intended to be used within low-fidelity aerostructural analysis tools to facilitate rapid design optimization and exploratory …
Sensitivity And Estimation Of Flying-Wing Aerodynamic, Propulsion, And Inertial Parameters Using Simulation, Jaden Thurgood, Douglas F. Hunsaker
Sensitivity And Estimation Of Flying-Wing Aerodynamic, Propulsion, And Inertial Parameters Using Simulation, Jaden Thurgood, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
This paper explores the difficulties of aircraft system identification, specifically parameter estimation, for a rudderless aircraft. A white box method is used in conjunction with a nonlinear six degree-of-freedom aerodynamic model for the equations of motion in order to estimate 33 parameters that govern the aerodynamic, inertial, and propulsion forces within the mathematical model. The analysis is conducted in the time-domain of system identification. Additionally, all the parameters are estimated using a single flight rather than a series of shorter flights dedicated to estimating specific sets of parameters as is typically done. A final flight plan is developed with a …
Comparison Of Theoretical And High-Fidelity Aerostructural Solutions, Jeffrey D. Taylor, Douglas F. Hunsaker
Comparison Of Theoretical And High-Fidelity Aerostructural Solutions, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
As contemporary aerostructural research in aircraft design trends toward high-fidelity computational methods, aerostructural solutions based on theory are often neglected or forgotten. In fact, in many modern aerostructural wing optimization studies, the elliptic lift distribution is used as a benchmark in place of theoretical aerostructural solutions with more appropriate constraints. In this paper, we review several theoretical aerostructural solutions that could be used as benchmark cases for wing design studies, and we compare them to high-fidelity solutions with similar constraints. Solutions are presented for studies with 1) constraints related to the wing integrated bending moment, 2) constraints related to the …
Improving Thermal Conduction Across Cathode/Electrolyte Interfaces In Solid-State Lithium-Ion Batteries By Hierarchical Hydrogen-Bond Network, Jinlong He, Lin Zhang, Ling Liu
Improving Thermal Conduction Across Cathode/Electrolyte Interfaces In Solid-State Lithium-Ion Batteries By Hierarchical Hydrogen-Bond Network, Jinlong He, Lin Zhang, Ling Liu
Mechanical and Aerospace Engineering Student Publications and Presentations
Effective thermal management is an important issue to ensure safety and performance of lithium-ion batteries. Fast heat removal is highly desired but has been obstructed by the high thermal resistance across cathode/electrolyte interface. In this study, self-assembled monolayers (SAMs) are used as the vibrational mediator to tune interfacial thermal conductance between an electrode, lithium cobalt oxide (LCO), and a solid state electrolyte, polyethylene oxide (PEO). Embedded at the LCO/PEO interface, SAMs are specially designed to form hierarchical hydrogen-bond (H-bond) network with PEO. Molecular dynamics simulations demonstrate that all SAM-decorated interfaces show enhanced thermal conductance and dominated by H-bonds types. The …
Numerical Method For Rapid Aerostructural Design And Optimization, Jeffrey D. Taylor, Douglas F. Hunsaker
Numerical Method For Rapid Aerostructural Design And Optimization, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
During early phases of wing design, analytic and low-fidelity methods are often used to identify promising design concepts. In many cases, solutions obtained using these methods provide intuition about the design space that is not easily obtained using higher-fidelity methods. This is especially true for aerostructural design. However, many analytic and low-fidelity aerostructural solutions are limited in application to wings with specific planforms and weight distributions. Here, a numerical method for minimizing induced drag with structural constraints is presented that uses approximations that apply to wings with arbitrary planforms and weight distributions. The method is applied to the NASA Ikhana …
Near-Field Pressure Signature Splicing For Low-Fidelity Design Space Exploration Of Supersonic Aircraft, Christian R. Bolander, Douglas F. Hunsaker
Near-Field Pressure Signature Splicing For Low-Fidelity Design Space Exploration Of Supersonic Aircraft, Christian R. Bolander, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
As interest in supersonic overland flight intensifies, new ways to meet government restrictions on sonic boom loudness must be implemented. Low-fidelity aerodynamic tools, such as PANAIR, can estimate the near-field pressure signature that ultimately determines the loudness of the sonic boom at the ground. These tools can greatly benefit the exploration of large design spaces due to their computational efficiency. One of the limitations of low-fidelity tools is the accuracy of the solution produced, which is dependent on the fundamental physical assumptions made in the development of the governing equations. If flow patterns are produced that severely violate these fundamental …
A Multi-Fidelity Prediction Of Aerodynamic And Sonic Boom Characteristics Of The Jaxa Wing Body, Forrest L. Carpenter, Paul G. A. Cizmas, Christian R. Bolander, Ted N. Giblette, Doug F. Hunsaker
A Multi-Fidelity Prediction Of Aerodynamic And Sonic Boom Characteristics Of The Jaxa Wing Body, Forrest L. Carpenter, Paul G. A. Cizmas, Christian R. Bolander, Ted N. Giblette, Doug F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
This paper presents a detailed comparison between the linear panel solver PANAIR A502 and the in-house Navier–Stokes solver UNS3D for a supersonic low-boom geometry. The high-fidelity flow solver was used to predict both the inviscid and laminar flow about the aircraft geometry. The JAXA wing body was selected as the supersonic low-boom geometry for this study. A comparison of the undertrack near-field pressure signatures showed good agreement between the three levels of model fidelity along the first 0.8L of the signature. Large oscillations in the PANAIR results were observed. The PANAIR discrepancies were traced back to violations of the …
A Procedure For The Calculation Of The Perceived Loudness Of Sonic Booms, Christian R. Bolander, Douglas F. Hunsaker, Hao Shen, Forrest L. Carpenter
A Procedure For The Calculation Of The Perceived Loudness Of Sonic Booms, Christian R. Bolander, Douglas F. Hunsaker, Hao Shen, Forrest L. Carpenter
Mechanical and Aerospace Engineering Student Publications and Presentations
Implementing a method to calculate the human ear’s perceived loudness of a sonic boom requires consulting scattered literature with varying amounts of detail. This work describes a comprehensive implementation of Stevens’ Mark VII in Python, called PyLdB. References to literary works are included in enough detail so that the reader could use this work as a guide to implement the Mark VII algorithm. The details behind the mathematics of the Mark VII algorithm are included and PyLdB is used to calculate the perceived loudness of an example pressure signature. PyLdB is benchmarked against a widely used and validated code by …
Numerical Algorithm For Wing-Structure Design, Jeffrey D. Taylor, Douglas F. Hunsaker, James J. Joo
Numerical Algorithm For Wing-Structure Design, Jeffrey D. Taylor, Douglas F. Hunsaker, James J. Joo
Mechanical and Aerospace Engineering Student Publications and Presentations
Low-fidelity aerostructural optimization routines have often focused on determining the optimal spanloads for a given wing configuration. Several analytical approaches have been developed that can predict optimal lift distributions on rectangular wings with a specific payload distribution. However, when applied to wings of arbitrary geometry and payload distribution, these approaches fail. Increasing the utility and accuracy of these analytical methods can result in important benefits during later design phases. In this paper, an iterative algorithm is developed that uses numerical integration to predict the distribution of structural weight required to support the bending moments on a wing with arbitrary geometry …