Phillip J. Ansell's research while affiliated with University of Illinois, Urbana-Champaign and other places

Publications (86)

Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-3662.vid Boundary-layer ingestion (BLI) and distributed propulsion (DP) are important concepts to future aircraft systems and technologies. Both BLI and DP have the potential to increase aircraft efficiency and improve aircraft design in various other ways. The present study aims to address se...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-3330.vid Phononic materials have rich frequency-dependent characteristics that can be designed into their geometry. These characteristics can open up new avenues for passively controlling flow instabilities with intrinsic frequency content. Recent numerical studies demonstrated the potential o...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-3525.vid When conducting shape optimization or aerodynamic design studies, one key step in the design process is the choice of a geometry parametrization method. A parametrization framework using a series of joined Bézier curves is proposed. This framework creates airfoil geometries satisfying...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-3214.vid An airfoil design method is proposed which considers the boundary-layer integral parameters as the driving design condition. The method consists of a parameterization for generation of a pressure distribution capable of producing desired boundary-layer characteristics, which is then u...
Conference Paper
This paper describes the analysis of a hydrogen fuel-cell-powered transport-category aircraft, similar in mission performance to a Boeing 737-800. The configuration examined produced peak waste heat loads up to 16 megawatts. Contemporary thermal dissipation systems, such as radiators, lead to a substantial drag contribution due to the large cooling...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-1677.vid A rotor blade design method is presented that aims to passively mitigate the formation of coherent tip vortex structures in the near-field of the rotor wake. The method leverages fundamentals principles of Helmholtz’s theorems, where the strength of the shed vortex wake is proportiona...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-1548.vid A plasma swirler, based on an existing Lorentz force driven gliding arcs, was developed as a flame holding and combustion enhancing device for premixed and diffusion flames. The device is intended to deliver the combined benefits of jet swirlers and plasma assisted combustion by provi...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-2257.vid Magnetically-guided atmospheric arc devices were applied to provide plasma-excitation to premixed methane-air flames. Researchers have recently applied similar technology to study vortex generation for aerodynamic flow control, and the scaling and driver circuits used for those device...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-1540.vid This paper describes a rotating lifting line framework used for the constrained design optimization of rotary wing systems. This method leverages a finite vortex element approach to represent the lifting line and shed circulation elements associated with the helical wake vortex system...
Article
Full-text available
Emission reduction in transportation requires advancements in aviation technologies enabling fully electrified propulsion, among which, the use of superconducting technologies can provide untapped benefits given their low weight and minimal losses for high-power transmission. However, to enable their use in aircraft electrical power systems additio...
Article
A study was performed to characterize an optimum return trajectory for a sailplane after a rope-break failure during an aerotow launch procedure. The performance of an SGS 1-26E sailplane was simulated using the equations of motion for quasi-steady flight in a time-stepping routine and published aerodynamic polar data. A gradient-based optimization...
Conference Paper
Full-text available
View Video Presentation: https://doi.org/10.2514/6.2021-3302.vid As the aviation industry focuses on increasing the sustainability of its technologies, fully electrified propulsion concepts are further explored and developed. One particular area of interest is in the development of hybrid propulsion aircraft using cryogenic cooling and components i...
Article
As distributed electric propulsion has continued to gain popularity as an enabling aircraft technology, further research is required to understand the complete implications of aeropropulsive coupling effects for distributed propulsion systems integrated into actual aircraft geometries. A set of low-speed wind-tunnel tests was performed at the Unive...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2021-2409.vid This study considers the aircraft configuration impact of a liquid hydrogen/fuel cell electric propulsion system when integrated into a single-aisle, transport-class aircraft having consistent performance capability of a Boeing 737-800. This study demonstrates that, given reasonable d...
Article
Full-text available
A series of experiments were conducted to understand the sources of local, high-amplitude velocity fluctuations produced at the late stages of boundary-layer flow transition to turbulence. The laboratory experiments considered the controlled injection of Tollmien-Schlichting (TS) waves into a nearly zero pressure gradient, laminar boundary layer, r...
Conference Paper
A genetic algorithm was used to design a morphing leading-edge shape on a slotted natural laminar flow airfoil in order to maximize the airfoil C_(l,max) while retaining a constant leading-edge arc length. The MSES program suite was used to evaluate a randomized population of airfoils during the design process at freestream conditions of M = 0.225...
Conference Paper
Proper orthogonal decomposition (POD) is applied to schlieren data of a Griffith-type transonic, laminar-flow airfoil across a range of angles of attack to analyze the influence boundary layer suction had on the shock oscillatory process. This particular class of airfoils utilizes active boundary-layer suction to assist an aggressive pressure recov...
Conference Paper
A series of experiments were conducted on a quasi-2D S8036 airfoil with a distributed electric propulsion (DEP) system. An overwing ducted fan system was tested with varied thrust angles achieved by deflecting the fan exit flow direction. The DEP system was comprised of five electric fans mounted on the upper surface of the airfoil trailing edge. T...
Conference Paper
An investigation was conducted to assess the ability of a boundary layer to remain attached across a Stratford pressure recovery in a transonic flow and to verify if recovery across shorter chordwise distances was possible with the aid vortex generators (VG). Airfoil geometries with Stratford-like pressure recovery regions approaching Cf,x = 0 were...
Conference Paper
A Bréguet Range Equation for a hybrid-electric (thrust-rated) jet aircraft was formulated by modifying the conventional Bréguet Range Equation derivation to incorporate a power-rated electric motor and battery energy source. The resulting ranges for conceptual hybrid-electric aircraft were compared to a hybrid-electric flight performance simulation...
Conference Paper
Full-text available
The aviation industry has been challenged to increase the sustainability of its technologies, which is the main driving force in research and exploration of fully electrified propulsion. This paper presents the initial steps in the design and modeling of the Cryogenic High-Efficiency Electrical Technologies for Aircraft (CHEETA) that would form the...
Article
The aeronautics industry has been challenged on many fronts to increase flight efficiency, reduce greenhouse gas emissions, and decrease dependence on traditional hydrocarbon fuels. Each year, aviation produces more than 900 million metric tons of CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</s...
Article
Dynamic stall experiments were performed on a NACA 0012 airfoil subjected to a constant pitch rate maneuver at three transitional Reynolds numbers of Rec=0.2×106, 0.5×106, and 1.0×106. The primary objectives of this investigation were to describe the evolution of the flow and to quantify the characteristic timescales of dominant fluctuations in the...
Conference Paper
Full-text available
A novel axisymmetric device with pulsed spark emission was developed as an active flow control alternative to passive vortex generators. The flowfield induced by the actuator was studied in quiescent flow. The current-voltage characteristics and power requirements of the high-voltage circuit that powered the discharge were detailed at different ope...
Article
Full-text available
A novel axisymmetric device with pulsed spark emission was developed as an active flow control alternative to passive vortex generators. The flowfield induced by the actuator was studied in quiescent flow. The current–voltage characteristics and power requirements of the high-voltage circuit that powered the discharge were detailed at different ope...
Article
The influence of aspect ratio (AR) on dynamic stall was studied by comparing experimental performance data and three-component velocity measurements acquired for wings of AR=3, 4, and 5, and an airfoil during an unsteady pitch maneuver. A NACA 0012 airfoil was used for all wing models, which were subject to a sinusoidal pitch oscillation between 4...
Article
An experimental test campaign was conducted on a transonic Griffith-type airfoil to evaluate the effectiveness of its laminar flow qualities and boundary-layer flow control characteristics in the transonic regime. From the pressure distributions it was observed that the flow control application had a beneficial influence, allowing for a more aggres...
Article
The multiscale development of dynamic stall was studied using a scale-based modal analysis technique. Time-resolved velocity field data around an airfoil during dynamic stall were used for this analysis, with experimental conditions corresponding to Rec=9.2×105 and k=0.05. Intrinsic mode functions were determined by a multivariate, multidimensional...
Article
A feasibility study of a hybrid-electric commercial transport aircraft was conducted by analyzing the simulated performance and lifecycle carbon dioxide (CO2) emissions of a conventional single-aisle aircraft and an aircraft with a modified parallel hybrid-electric propulsion system. A flight performance simulation was developed in a MATLAB/Simulin...
Article
A series of wind-tunnel experiments was conducted on a dynamically pitching NACA 0012 airfoil in order to understand the unsteady flow physics associated with dynamic stall at a transitional Reynolds number of Rec=0.5×106. The airfoil was pitched about the quarter-chord axis following a linear ramp maneuver at ω+=0.05. A series of high-frequency un...
Article
Full-text available
The current study considers an analysis of hyperelliptic cambered span wing configurations, optimized for minimum drag. This study encompasses a multidimensional design optimization approach wherein the wing geometries are optimized with respect to both span load and spanwise camber to achieve minimum aerodynamic drag. A discrete vortex element met...
Article
Full-text available
The system-level capabilities and component-level sensitivities of hybrid-electric propulsion systems were analyzed by modeling a twin-engine general-aviation aircraft. The flight-performance model was developed using performance variables for the Tecnam P2006T found in published papers authored by the aircraft manufacturer. Both parallel and serie...
Article
Over the last decade, empirical mode decomposition (EMD) has developed into a versatile tool for adaptive, scalebased modal decomposition. EMD has proven to be capable of decomposing multivariate signals with cross-channel mode alignment. However, the algorithms for envelope identification in multivariate EMD come with a computational burden render...
Article
This study aims to characterize the complex propulsive-airframe and cross-propulsor interactions that occur on an overwing distributed propulsion system with boundary-layer ingestion. Wind tunnel experiments were performed on a NACA 643–618 airfoil model with an array of five ducted fans integrated across the upper-surface trailing edge. Net forces...
Article
A computational study on the wake characteristics of span-optimized wings is discussed, where the effect of the wing spanload on the resulting wake rollup characteristics and structure is emphasized. Two wing configurations, each optimized for minimum induced drag at a fixed C L and fixed bending-moment constraint, are studied; and their wake chara...
Article
The current study was conducted to understand flowfield unsteadiness associated with static stall hysteresis on a NACA 0012 airfoil at Rec=1.0×106. Unsteady pressure measurements were acquired to evaluate the performance of the airfoil, and the presence of a hysteresis loop was identified in the vicinity of the airfoil Cl,max. At poststall angles o...
Article
Active unsteady flow control experiments were performed on a natural laminar flow airfoil at Rec = 1.0 × 10⁶. The goal of this study was to control boundary-layer separation across the trailing-edge region of the airfoil in off-design conditions. Active control of separation was achieved using a series of blowing slots at the x/c = 0.75 location. A...
Article
An evaluation and analysis of optimum wing spanloads was conducted by comparing wing performance values obtained from theoretical models and experimental wind-tunnel measurements. Three wing spanloads were designed for a prescribed lift and wing root bending moment using a Lagrange multiplier optimization method, with and without incorporating a re...
Article
Empirical mode decomposition has been shown to be a valuable data analysis tool in a wide array of technical fields, and it has recently emerged as a useful technique for studying complex fluid flows. This technique is useful for separating relevant unsteady spatiotemporal scales from a signal through an adaptive, iterative data-processing algorith...
Conference Paper
An experimental investigation was conducted on an NACA 0012 airfoil with a leading-edge horn-ice shape to identify and characterize flowfield unsteadiness related to ice-induced flow separation. This type of iced-airfoil flowfield was dominated by a leading-edge separation bubble, which is associated with several inherent modes of unsteadiness. Usi...
Article
A study was conducted to demonstrate the application of a hinge-moment-based envelope protection system on a wing. All measurements were acquired on a straight, tapered semispan wing model with a NACA 3415 cross section across the entire semispan. The NACA 3415 airfoil was used in constructing the wing model, as it was the same airfoil section that...
Conference Paper
An experimental investigation was conducted on an NACA 0012 airfoil with a leading-edge horn-ice shape to identify and characterize flowfield unsteadiness related to ice-induced flow separation. This type of iced-airfoil flowfield is dominated by a leading-edge separation bubble, which is associated with several inherent modes of unsteadiness. Usin...
Article
Wind-tunnel measurements were used to identify and characterize the low-frequency oscillation present in the flowfield about an NACA 0012 airfoil with a horn-ice shape. This low-frequency mode was identified in the unsteady content of the airfoil lift coefficient and the corresponding Strouhal numbers compared well with those reported in the litera...
Article
An innovative method for determining the unsteady shear-layer reattachment location downstream of a flow obstacle using a surface-mounted hot-film array is proposed. The method uses strong levels of anticorrelation between adjacent probes across short time windows to determine the unsteady location of shear-layer reattachment. The resulting time hi...
Conference Paper
High lift multielement airfoils, such as those used on large transport aircraft during takeoff and landing, can generate strong adverse pressure gradients that, while the surface flow is attached, can cause off-thesurface separation in the wake, so called, wake bursting. The sudden expansion and thickening of the separated wakes has been shown to de...
Conference Paper
A hinge moment based stall prediction method originally designed using 2D airfoil data is extended to a 3D wing. Experimental hinge moment measurements were obtained for a NACA 3415 semispan wing model in a clean configuration and with various simulated leading-edge contaminants. The effects of the simulated contamination configurations on the 3D w...
Conference Paper
Wind tunnel measurements were used to determine the unsteady location of shear-layer reattachment on an NACA 0012 airfoil with a leading-edge horn-ice shape, along with the corresponding time-resolved unsteady iced-airfoil performance. Similar trends in lowfrequency content were identified between the unsteady shear-layer reattachment location and...
Article
A stall prediction method based on unsteady hinge moment measurements was previously developed from experimental hinge moment measurements on a NACA 3415 airfoil model under a clean configuration and four iced configurations. The stall prediction algorithm was based on three separate detector functions. Additional hinge moment measurements have bee...
Conference Paper
The purpose of this investigation was to explore the feasibility of utilizing flap and control surface hinge moments to provide stall warning for flight vehicles. The ultimate goal would be to provide a robust flight envelope protection system. Hinge moment data were acquired for a flapped NACA 3415 airfoil model in the 3-ft × 4-ft wind tunnel at t...

Citations

... So, any utilization of HTS cables in these aircraft, must be conducted with respect to the cryogenic properties of LH 2 . This can impact the fault current amplitude, safety margin, and even type of utilised tape [204]. ...
... Previous wind tunnel studies have developed combined propulsion and airframe aerodynamic, or aero-propulsive, models for distributed propulsion eVTOL aircraft with significant propulsion-airframe interactions [29,30]. Other wind tunnel research has studied aero-propulsive interaction effects for fixed-wing aircraft with distributed electric fans mounted on the wing [31,32]. ...
... Previous works have derived the mathematical models utilized in the current study and conducted experiments using liquid hydrogen (LH 2 ) to derive thermal response characteristics of the line [1], [2]. The electrical power systems subjected to the fault tests in this study were specified based on the CHEETA electrified aircraft system [3], and earlier models of the HTS lines and their application and integration with the CHEETA power system are described in [4]. ...
... For a turbo-electric aircraft such as the STARC-ABL concept [10], the kW-scale thermal loads could be managed by outer mold line (OML) heat exchangers [11]. The limits on the available aircraft surface area, make this strategy impractical as the sole solution for the MW-scale thermal loads of a fuel-cell-powered aircraft such as CHEETA [12]. Conventional radiator-type cooling systems introduce substantial parasitic drag penalties, mainly due to skin friction on additional ducting and radiator surface area [12]. ...
... i.e., i = 1, needs to be retained, but is not clear in a boundary layer flow, which will be tested in this work by considering the suboptimal modes in Eq. (14). Another similar approach to reconstruct transitional boundary layer flow is based on the dominant modes from proper orthogonal decomposition (POD) 23 . ...
... Previous works have derived the mathematical models utilized in the current study and conducted experiments using liquid hydrogen (LH 2 ) to derive thermal response characteristics of the line [1], [2]. The electrical power systems subjected to the fault tests in this study were specified based on the CHEETA electrified aircraft system [3], and earlier models of the HTS lines and their application and integration with the CHEETA power system are described in [4]. ...
... Air transportation is considerably more damaging than the emission figures represent (Van Fan et al., 2018;Chapman, 2007;Larsson et al., 2018;Yu et al., 2020;Ansell and Haran, 2020). In the EU, air transportation is responsible for 13.3% of greenhouse gas production in the transportation area (Van Fan et al., 2018). ...
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