bluuebunny/crossref_metadata_2025_split huggingface dataset:
The CFD Modeling of the Water Braking Phenomena for the Holloman High-Speed Test Track
Authors: Terrazas Jose , Kotteda V. M. Krushnarao , Kumar Vinod , Edmonds Robert , Zeisset Michelle 
Published: November 2019

Abstract
At the Holloman High-Speed Test Track (HHSTT), momentum exchange with water is used to decelerate sleds from very high speeds (&gt; Mach 1). This process, at the HHSTT, is called ‘water braking’. Improving the prediction capabilities of water braking phenomena has the potential to result in radical changes in the designs of sleds, improve rocket sled velocity-time test profile predictions, provide greater confidence of braking mechanisms, and decrease risk in the recovery of critical infrastructures. Understanding the water?s behavior with the sled is critical to predicting how the water could damage the sled, which affects the recoverability of the sled and can determine the success of a mission. Traditionally, sled design for the test missions for water braking has been guided by empirical/hand calculations to estimate the forces on various components. The calculations involved various approximations in arriving at the force balance law and predicting the acceleration/deceleration profile. In partnership with the HHSTT, we performed preliminary simulations to develop a predictive model for the HHSTT sled tests at various velocity regimes. The (preliminary) CFD results from different geometry configurations for the sled and modeling parameters will be presented.
Exploring and Improving the Flow Characteristics of an Empty Water Channel Test Section: The Application of TomoPIV and Flowrate Sensors for Whole-Flow-Field Visualization
Authors: Mousavi sani Seyedmohammad , Goudarzi Navid , Sheikhshahrokhdehkordi Mohammadamin , Bisel Tucker , Dahlberg Jerry , Tkacik Peter 
Published: November 2019

Abstract
This paper presents the quantitative results of improving the uniformity of the flow field within the test section of a constant cross section, closed-loop water channel. Tomographic Particle Image Velocimetry (TomoPIV) and four flowrate sensors are used to determine the mean velocity and velocity fluctuations at two motor frequencies: 7.5 Hz and 10 Hz (an approximate free stream flow velocity of 0.11 m/s and 0.18 m/s, respectively). The flow field velocity determined by the flowrate sensors showed great agreements with the TomoPIV results. For instance, at the 10 Hz water channel motor frequency, the flowrate sensors and TomoPIV obtained velocity ranges of 0.191–0.202 m/s and 0.185–0.21 m/s, respectively. In order to reduce the flow speed variations within the studied TomoPIV measurement volume, improvements were implemented on the water channel to include an adjustable screen and deflector to the first set of turning vanes downstream from the water channel motor. The modification improved the 7.5 Hz motor frequency measured flow velocity from 0.16–0.172 m/s to 0.106–0.108 m/s resulting in a final variation of flow speed within the measurement volume reduced to 1%.
Branch and Bound Analysis to Characterize Phase Variations in Laser Propagation Through Deep Turbulence
Authors: Rodriguez Luis F. , Kumar Vinod , Espiritu Jose , Bronson Arturo , Kotteda Krushnarao , Lozano Diego , Rodriguez Arturo 
Published: November 2019

Abstract
An analytical estimation of the wave diffraction due to turbulence is made and then it is compared with an estimate based on the Branch and Bound technique as a platform of a machine learning model. At the final step, the results are compared to verify the capacity of the machine learning model.
The reason for this analysis is based on the fact that communication via laser beam in the open atmospheric environment experiences the effects of the turbulence generating a disturbance of wave phases that affects the fidelity of such communication.
Theoretical Optimization of Splitter Blade Geometry in High-Efficiency Centrifugal Turbopumps
Authors: Apollonio Alessandro , Maddaluni Francesco , Pasini Angelo , Valentini Dario , d’Agostino Luca 
Published: November 2019

Abstract
The introduction of splitter blades (splitters) in the impeller represents a possible way to improve the head and efficiency of centrifugal turbopumps. Splitters decrease flow slip, deviation, blockage and losses at the impeller discharge by reducing the displacement flow and the adverse pressure gradient it induces on the boundary layers (BLs) developing on the pressure sides of the full blades. These benefits are to be balanced against the introduction of additional flow blockage and losses. It is therefore of interest to investigate which splitter blade geometry (position and length), if any, is most effective to best exploit the potential advantages of adding splitter blades to a centrifugal impeller. To this purpose a quasi-3D, reduced-order method, previously developed for preliminary prediction of the geometry and performance of centrifugal turbopumps, is extended to account for the introduction of splitter blades for the purpose of investigating their influence on the hydraulic performance of these machines. Splitters with radial leading edges and the same shape as the full blades are introduced in the six-bladed backswept impeller of the VAMPIRE turbopump, a high-efficiency machine previously used for experimental validation of the original version of the flow model. The results highlight the most relevant action mechanisms of splitter blades in affecting the turbopump performance and provide general indications on their most effective design for performance improvement. As a consequence of the evolution of the BLs in the blade channels, relatively longer splitters located closer to the pressure sides of the full blades are more efficient at and above design flow, while the reverse is the case at high blade loadings. The results also indicate that the introduction of splitter blades only marginally improves the performance of the already optimized VAMPIRE pump in view of its small residual margins for performance gains.
Thermal Cavitation Instability Analysis in Axial Inducers by Means of Casing and Hub-Mounted Pressure Sensors
Authors: Hadavandi Ruzbeh , Pasini Angelo , Valentini Dario , Pace Giovanni , d’Agostino Luca 
Published: November 2019

Abstract
The effects of thermal cavitation on the flow instabilities developing in a three-bladed, tapered-hub, variable-pitch space turbopump inducer are described by illustrating the results of similarity experiments in water carried out at Sitael in the Cavitating Pump Rotordynamic Test Facility (CPRTF). The operating conditions have been varied as required for investigating the onset and response of the fluid dynamic instabilities occurring in the test inducer over a wide range of cavitation numbers from noncavitating to heavy cavitation conditions, both at design and off-design flow. The CPRTF water temperature has been varied from room conditions to 80 °C ca. in order to induce thermal cavitation effects of increasing intensity capable of reproducing in the experiments the occurrence of typical cavitation phenomena in cryogenic space propellants. A wide variety and number of axial and rotating fluid dynamic instabilities have been detected, identified and characterized by spectral analysis of the pressure measurements obtained from statoric and rotoric transducers flush-mounted on the casing and the hub of the test inducer. The results indicate that thermal cavitation significantly affects the types of flow instabilities developing in cavitating inducers and the range of flow and suction conditions for their occurrence.
2D Velocity Vector Profile Measurement and Phase Separation on Swirling Bubbly Flow Using Ultrasound Technique
Authors: Wongsaroj Wongsakorn , Takahashi Hideharu , Kikura Hiroshige , Thong-un Natee 
Published: November 2019

Abstract
Two-phase swirling bubbly flow is a complex phenomenon which occurs in several industries such as a nuclear reactor. Its characteristic is indispensably necessary to be investigated especially the multi-dimensional velocity distribution. This present paper describes the development of Ultrasonic Velocity Profiler (UVP) method which is a noninvasive measurement and needless of optical access, to obtain a two dimensional (2D) velocity distribution of the bubble and liquid phase in swirling bubbly flow simultaneously. The measurement result is represented in the form of the 2D velocity vector. To achieve the target, the multiple transducers and developed signal processing have been applied to the UVP system to measure a 2D velocity vector affected by bubble and liquid separately. For confirming the ability of Developed-UVP, the experiment was conducted on a vertical pipe co-current flow apparatus. The UVP measurement was demonstrated non-intrusively and without the optical requirement. The measurement applicability of Developed-UVP was evaluated by comparing with Particle Image Velocimetry (PIV) method on liquid flow and bubbly flow. Then, it was applied to obtain the 2D velocity vector in swirling bubbly flow. The velocity vector of the bubble and liquid could be separated clearly. Also, velocity distribution in swirling motion which was interacted of both phases was investigated understandably by using this measurement technique.
LDV Measurement of Turbulent Pipe Flow With Traveling Wavy Elastic Wall for Drag Reduction
Authors: Nakazawa Seiya , Shimura Takaaki , Mitsuishi Akihiko , Iwamoto Kaoru , Murata Akira 
Published: November 2019

Abstract
Drag reduction effect by traveling wavy wall deformation control in turbulent pipe flow was experimentally investigated. From the visualization, we confirmed the downstream traveling wave although it was not uniform in the circumferential direction. When the frequency is 110 Hz, the wall deformation amplitude and the wavelength indicated that the effective values for drag reduction. The wavespeed is approximately effective values for drag reduction. As a result, the maximum drag reduction rate of 6.8 % is obtained. The result of a LDV measurement shows that the mean streamwise velocity gradient decreased near the wall by the control, which leads to drag reduction.
A Hierarchical Bayesian Method for Time Domain Structure Damage Detection
Authors: Feng Wei , Li Qiaofeng , Lu Qiuhai 
Published: November 2019

Abstract
A time domain structural damage detection method based on hierarchical Bayesian framework is proposed. Due to local stiffness reductions, the responses of damaged structures vary from those in undamaged status under the same external excitation. In this paper, the responses of damaged structures are assumed as the result of a summation of known external forces and unknown virtual forces exerted on corresponding undamaged structures. The damages can thus be detected, located, and quantified by the identification of associated virtual forces. A hierarchical Bayesian formulation considering all undetermined damage-related variables is adopted for the identification of virtual forces. The reasonable values of the variables and their uncertainties are depicted by their posterior distributions, sampled by Markov chain Monte Carlo method. Compared with traditional Bayesian formulations, manual choice of prior parameters is avoided and less prior information is required. The proposed virtual force indicator provides a more intuitive perspective for damage detection tasks and is potentially more operable in engineering practice. These advantages are illustrated by simulation of a cantilever beam under various damage conditions.
Cross-Well Dynamics of Bistable Cross-Ply Laminates
Authors: Emam Samir A. , Inman Daniel J. 
Published: November 2019

Abstract
This paper presents an experimental analysis of the dynamic response of bistable composite laminates that are harmonically excited. Bistable composite laminates are unsymmetric thin laminates that possess two self-equilibrated positions at room temperature. The resonant frequencies of bending under small harmonic excitations have been identified to serve as natural frequencies of the underlying linear system. Amplitude sweep and frequency sweep have been performed and the plate’s dynamics has been identified and analyzed. Four-ply and eight-ply laminates have been tested and showed similar behavior. The main conclusion is that when the cross-ply bistable laminates are harmonically excited and either the excitation amplitude or resonant frequency is varied, the single-well dynamic response experiences a period-doubling bifurcation and a cross-well harmonic response is obtained. Chaotic cross-well response was also identified.
Energy Dissipation of Damper Rings for Thin-Walled Gears
Authors: Li Zichao , Wang Yanrong , Jiang Xianghua , Ye Hang , Yang Weichao 
Published: November 2019

Abstract
When the gear generates a nodal mode shape vibration, there are two directions of possible relative displacement between the corresponding points on the contact surface of the damper ring and the damper groove, which are circumferential direction and axial direction respectively. In this paper, the relative displacement of the damper ring and the damper groove are considered in two directions, and the calculation method of energy dissipation is proposed. When the nodal vibration occurs in the gear, due to the existence of the strain difference between the damper ring and the damper groove on the contact surface, circumferential slip of partial area would occur. The energy dissipation in one vibration cycle is accurately determined by analytical solution. Since the aviation gears are mostly thin-walled structures, the axial displacement is large when resonance occurs. Based on the discrete damper ring model which considers interaction between every segment of the ring, the first-order harmonic balance method is used to calculate the axial displacement of the damper ring under the given gear rim amplitude. And then the hysteresis curve area of each discrete segment on the contact surface is summed to obtain energy dissipation in one vibration cycle. In this paper, based on the energy method, the damping effect of the damper ring is predicted. The damping ratio curve obtained by energy dissipation in two directions is compared and analyzed. The occurrence conditions of the two directions of possible relative displacement and the influence of the damper ring parameters on both situations are summarized.
Topology Design and Analysis of a Novel 3-Translational Parallel Mechanism With Analytical Direct Position Solutions and Partial Motion Decoupling
Authors: Shen Huiping , Chablat Damien , Zeng Boxiong , Yang Ting-li 
Published: November 2019

Abstract
According to the topological design theory and method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations, this paper design a novel 3-translation (3T) PM that has three advantages, i.e., (1) it consists on three actuated prismatic joints, (2) the PM has analytical direct position solutions, and (3) the PM is of partial motion decoupling property. Firstly, the main topological characteristics such as the POC, degree of freedom and coupling degree are calculated for kinematics modelling. Due to the special constraint feature of the 3-translation, the analytical direct position solutions of the PM can be directly obtained without needing to use one-dimensional search method. Further, the conditions of the singular configuration of the PM, as well as the singularity location inside the workspace are analyzed according to the inverse kinematics.
Coupled Origami Tubes for Stiff Deployable Cantilevers
Authors: Filipov Evgueni T. , Tachi Tomohiro , Paulino Glaucio H. 
Published: November 2019

Abstract
Thin sheets folded into three dimensional origami structures can be useful in various engineering applications. This work explores the stiffness of deployable origami tubes used as cantilevers. A unique “zipper” configuration is used to couple the tubes, which makes the systems easy to deploy, yet stiff for other deformation modes. The self-restricting geometry of the coupled tubes limits local deformations and makes the systems stiff for out-of-plane loading. The global deployment characteristics are explored using eigenvalue band-gaps, and indicate that tubes with lower sector angles are easy to deploy yet also stiffer for unintended motions. Cantilever analyses show that the geometry of the coupled tubes can significantly affect the stiffness, with some tube combinations having a high orthogonal stiffness throughout deployment, while others only having a high stiffness when fully deployed. Parametric studies are used to show optimal geometries for the coupled tubes that maximize the eigenvalue band-gaps and the stiffness throughout the deployment. The coupled tubes could serve applications such as adjustable robotic arms, and deployable space booms with a reliable extension sequence.
Optimization of Machine Tool Settings on Hypoid Gear Dynamics
Authors: Lin Chia-Ching , Wang Yawen , Lim Teik C. , Zhang Weiqing 
Published: November 2019

Abstract
Hypoid gears are widely used to transmit torque on cross axis shafts in a vehicle rear axle system. The dynamic responses of these hypoid geared rotor system have a significant effect on the performance of noise, vibration, and harshness (NVH) for the vehicle design. From past studies, the main source of excitation for this vibration energy comes from hypoid gear transmission error (TE). Thus, the design of hypoid gear pair with minimization of TE is one way to control the dynamic behavior of the vehicle axle system. In this paper, an approach to obtain minimum TE and improved dynamic response with optimal machine tool setting parameters for manufacturing hypoid gears is discussed. A neural network, named Feed-Forward Back Propagation (FFBP), with Particle Swarm Optimization (PSO) and Gradient Descent (GD) training algorithms are used to predict the TE. With the optimal machine tool setting parameters, a 14 degrees of freedom geared rotor system analysis is performed to verify the improvement on dynamic response aiming at minimizing the TE. A case study of a hypoid gear pair with specified design parameters and working condition is presented to validate the proposed method. The results conclude that minimization of TE, the main excitation of vehicle axle gear whine noise and vibration, with optimal machine tool setting parameters can improve the overall dynamic response. The proposed approach provides a better understanding of an optimal design hypoid gear set to minimize TE and effect on vehicle axle system dynamics.
Study on Path Planning of Involute Tooth Surface Milling With General Cutting Tool
Authors: Shi Zhaoyao , Feng Zhipeng , Wang Peng 
Published: November 2019

Abstract
Milling involute tooth surface with universal cutting tool overcomes the difficult problem of customizing tool for nonstandard gear machining. It is difficult for gear manufacturers to gain an advantage in market competition because of the long cycle of customized cutting tools. In this paper, the milling path of involute tooth surface by a general cutting tool is studied, and how to obtain the uniform surface roughness of involute tooth surface and the cutting path scheme of cutting tool is discussed. The key point of this paper is to put forward the scheme of tool path in the milling process. The end profile of involute gear is modeled by an analytic method, and the equidistant contour of the profile of involute gear is established by using the principle of normal deviation, which provides an accurate position point for the cutting tool.
Sustainable Design of Residential Net-Zero Energy Buildings: A Multi-Phase and Multi-Objective Optimization Approach
Authors: Lan Lan , Wood Kristin L. , Yuen Chau 
Published: November 2019

Abstract
Zero energy building (ZEB) is an important concept for sustainable building design. This paper introduces a holistic design approach for residential net-zero energy buildings (NZEB) by adopting the Triple Bottom Line (TBL) principles: social, environmental, and financial. The proposed approach optimizes social need by maximizing thermal comfort time of natural cooling, and visual comfort time of daylighting. The environmental need is addressed by optimizing energy efficiency, and the financial need is addressed by optimizing life cycle cost (LCC). Multi-objective optimizations are conducted in two phases: the first phase optimizes the utilization rate of natural cooling and daylighting, and the second phase optimizes energy efficiency and LCC. Sensitivity analysis is conducted to identify the most influential variables in the optimization process. The approach is applied to the design of a landed house in a tropical country, Singapore. The results provide a framework and modeled cases for parametric design and trade-off analysis toward sustainable and livable built environment.
Bio-Oil Upgrading via Micro-Emulsification and Ultrasound Treatment: Examples for Analysis and Discussion
Authors: Hansen Samuel , Mirkouei Amin 
Published: November 2019

Abstract
Blended fuels allow biofuels (e.g., bio-oil, ethanol, and biodiesel) to be commercialized by mixing them with petroleum-based fuels and address their deficiencies, such as compatibility with existing engine systems. Traditional blends (e.g., B20, E15, and E85) rely on mechanical mixing and use of surfactants (stabilizing chemicals) to prevent mixture separation, however, in many cases bio-blends suffer from reduced performance. Bio-oil, a low-grade liquid biofuel, has high potential in blended fuels production and addresses its deficiencies, such as high upgrading cost due to high oxygen-carbon ratio and H2O content. Emulsion technology is a relatively immature process, which relies on microscopic H2O blended with fuel for increased performance and stability. This study explores how residual H2O in bio-oil may increase performance and compensate for its deficiencies by using bio-oil in diesel emulsion. Our research shows that (a) H2O emulsion fuel has received little attention yet, which can offer many benefits to reduce fuel consumption and emissions, (b) H2O content in bio-oil may be significant enough to impact performance in a diesel engine if stability concerns are addressed, and (c) the stability of bio-oil derived diesel emulsions may be increased over conventional practice, using ultrasonic cavitation. It is concluded that emulsified bio-oil in diesel is able to address common upgrading challenges by skipping H2O removing operation and using H2O in bio-oil to enhance blended fuel performance. Ultimately, bio-oil can be used to supplement diesel fuel and develop a commercial market similar to the strategy’s used earlier with ethanol production from corn.
Using Complex Orthogonal Decomposition to Extract Dispersion Relationships for Mass Chain
Authors: Valente N. A. , Caldwell R. A. 
Published: November 2019

Abstract
Complex orthogonal decomposition (COD) was used to determine the extracted dispersion relationship of a traveling wave in a mass chain. When COD extracts a wavenumber it will produce M values for each wavenumber, γi, and N values for each frequency, ωi; where M is the number of masses and N is the number of time samples. In this work, least squares and a simple mean of the M-γi’s and N-ωi’s extracted values were used to determine each γi and ωi, respectively. An analytical dispersion relationship for the mass chain is derived in addition to an approximate dispersion relationship. The approximate derivation was found using Lindstedt-Poincaré’s perturbation method. Lastly, the effects of the sampling rate on parameter extraction was studied. COD could accurately extract the wavenumber and frequency of a traveling wave in the mass chain. Using a simple mean provided marginally better results than that of least squares. Sampling at the Nyquist criterion gave accurate results which improved both marginally and asymptotically as the sampling rate increased.