bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Transfer Analysis in a Rotating Cavity With Axial Through-Flow
Authors: Puttock-Brown M. R. , Long C. A. 
Published: February 2021

Abstract
This paper presents local Nusselt numbers computed from experimental measurements of surface temperature of compressor disks in a multiple rotating cavity test rig with axial throughflow. A validated two-dimensional (2D) steady-state heat conduction analysis methodology is presented, using the actual test geometry, and 95% confidence intervals calculated using Monte Carlo simulation. Sensitivity of the solution to curve fitting types, geometric simplification, and surface instrumentation are explored. The results indicate that polynomial curves fits, while computational simple, are unsuitable especially at higher orders. It is shown that geometric simplifications, that typically simplify the algorithmic implementation, may also omit significant variation in heat flux at critical stress relieving locations. The effect of reducing measurement points in the analysis is to both overpredict heat transfer and increase the uncertainty of the results. Finally, the methodology is applied to previously published thermal data from the University of Sussex, facilitating qualitative discussion on the influence of the governing parameters. While this study does not overcome the inherent uncertainty associated with inverse solutions, it is intended to present a methodology that is readily available to the wider community for the analysis of thermal test data and suggests some guidelines at the planning and postprocessing stages. The range of experiment reported here covers: 1.13 × 105 &lt; Rez &lt; 5.14 × 105, 1.65 × 106 &lt; Reθ &lt; 3.16 × 106, 0.10 &lt; Ro &lt; 0.60, and 3.40 × 1011 &lt; Gr &lt; 1.25 × 1012.
Nozzle Passage Endwall Effectiveness Values With Various Combustor Coolant Flowrates—Part 1: Flowfield Velocity and Coolant Concentration Measurements
Authors: Nawathe Kedar P. , Zhu Rui , Lin Enci , Kim Yong W. , Simon Terrence W. 
Published: February 2021

Abstract
The stators of the first stage of a gas turbine are exposed to severe temperatures. The coolant streams introduced to prevent the stators from thermal damage further complicate the highly three-dimensional vane passage flow. Recent results have shown that the coolant streams injected for cooling the combustor also influence the flow physics and the cooling effectiveness in the first-stage stator vanes passage. However, the effects of changing the mass flowrate of these combustor coolant streams on the passage flowfield have not been studied. As understanding the coolant transport is necessary for analyzing changes in cooling effectiveness in the vane passage, detailed aerodynamic and thermal measurements along the whole vane passage are required. This two-part paper presents such measurements taken for a variety of combustor coolant and endwall film coolant flowrates. The experiments were conducted in a low-Mach number facility with engine-representative Reynolds numbers and large-scale high-level turbulence. The objective of the first part is to describe the flow that influences endwall and vane surface cooling effectiveness distributions, which are presented in the second part. The measurements show changes in the passage flowfield due to changes in both combustor coolant and endwall film coolant flowrates. Overall, the flow physics remains largely unaffected by changes in coolant flowrates except in the endwall-vane surfaces region where the combustor coolant flowrate dominates changes in coolant transport. This is shown to have a high impact on endwall and vane surface cooling.
Nozzle Passage Endwall Effectiveness Values With Various Combustor Coolant Flowrates—Part 2: Endwall and Vicinity Surface Effectiveness Measurements
Authors: Nawathe Kedar P. , Zhu Rui , Lin Enci , Kim Yong W. , Simon Terrence W. 
Published: February 2021

AbstractEffective coolant schemes are required for providing cooling to the first-stage stator vanes of gas turbines. To correctly predict coolant performance on the endwall and vane surfaces, these coolant schemes should also consider the effects of coolant streams introduced upstream in the combustor section of a gas turbine engine. This two-part paper presents measurements taken on a first-stage nozzle guide vane cascade that includes combustor coolant injection. The first part of this paper explains how coolant transport and coolant-mainstream interaction in the vane passage is affected by changing the combustor coolant and endwall film coolant flowrates. This paper explains how those flows affect the coolant effectiveness on the endwall and vane surfaces. Part one showed that a significant amount of coolant injected upstream of the endwall is present along the pressure surface of the vanes as well as over the endwall. Part two shows effectiveness measurement results taken in this study on the endwall and pressure and suction surfaces of the vanes. Sustained endwall coolant effectiveness is observed along the whole passage for all cases. It is uniform in the pitch-wise direction. Combustor coolant flow significantly affects cooling performance even near the trailing edge. The modified flowfield results in the pressure surface being cooled more effectively than the suction surface. While the effectiveness distribution on the pressure surface varies with combustor and film coolant flowrates, the distribution along the suction surface remains largely unchanged.
Simultaneous Bayesian Calibration and Engineering Design With an Application to a Vibration Isolation System
Authors: Ehrett Carl , Brown D. Andrew , Kitchens Christopher , Xu Xinyue , Platz Roland , Atamturktur Sez 
Published: February 2021

Abstract
Calibration of computer models and the use of those design models are two activities traditionally carried out separately. This paper generalizes existing Bayesian inverse analysis approaches for computer model calibration to present a methodology combining calibration and design in a unified Bayesian framework. This provides a computationally efficient means to undertake both tasks while quantifying all relevant sources of uncertainty. Specifically, compared with the traditional approach of design using parameter estimates from previously completed model calibration, this generalized framework inherently includes uncertainty from the calibration process in the design procedure. We demonstrate our approach to the design of a vibration isolation system. We also demonstrate how, when adaptive sampling of the phenomenon of interest is possible, the proposed framework may select new sampling locations using both available real observations and the computer model. This is especially useful when a misspecified model fails to reflect that the calibration parameter is functionally dependent upon the design inputs to be optimized.
Ultrasonic Wave Propagation Analysis in Cast Stainless Steel With Solidification Grain Structure Predicted by Cellular Automaton Finite Element Approach
Authors: Nagai Masaki , Lin Shan , Nakahata Kazuyuki 
Published: February 2021

Abstract
Several components of nuclear power plants are made of cast austenitic stainless steel (CASS) because of its high corrosion resistance and strength. The inservice inspection based on ultrasonic testing (UT) has to be conducted for CASS components in accordance with fitness-for-service codes such as the Japan Society of Mechanical Engineers Rules on Fitness-for-Service for Nuclear Power Plants. However, a high-accuracy evaluation of flaws in CASS components through UT is difficult because the ultrasonic waves are scattered and attenuated by coarse grains, and their beam is distorted by the anisotropy resulting from the grain orientations. Numerical simulations are useful and reasonable ways for better understanding the ultrasonic wave propagation behavior in CASS. To effectively achieve this, the simulation model should include a three-dimensional (3D) grain structure. If a casting simulation can predict the solidification structure in a CASS, the wave propagation could be simulated also for a more realistic situation. In this study, we predicted the solidification structure of statically CASS by using a cellular automaton (CA) coupled with the finite element method and fed this structure into an explicit finite element model (FEM) for simulating the propagation of waves emitted by angle beam probes. Afterward, these simulated wave propagations were compared with those measured by a 3D laser Doppler vibrometer (LDV), showing almost good agreement between predicted and experimental results.
A Formal Representation of Conjugate Verbs for Function Modeling
Authors: Chowdhury Ahmed , Venkatanarasimhan Lakshmi N. A. , Sen Chiradeep 
Published: February 2021

Abstract
Modern design problems often require multi-modal, reconfigurable solutions. Function modeling is a common tool used to explore solutions in early mechanical design. Currently, function modeling formalisms minimally support the modeling of multi-modal systems in a formal manner. There is a need in function modeling to capture multi-modal system and analyze the effects of control signals and status signals on their operating modes. This paper presents the concept of functional conjugacy, where two function verbs or functional subgraphs are topological opposites of each other. The paper presents a formal representation of these conjugate verbs that formally captures the transition from one mode of operation to its topological opposite based on the existence of, or the value of, signal flows. Additionally, this paper extends functional conjugacy to functional features, which supports conjugacy-based reasoning at a higher level of abstraction. Through the example of a system-level function model of a geothermal heat pump (GHP)operating in its heating and cooling modes, this paper demonstrates the ability to support modal reasoning on function models using functional conjugacy and illustrates the modeling efficacy of the extended representation.
Fluid Dynamics of a Bistable Diverter Under Ultrasonic Excitation—Part II: Flow Visualization and Fundamental Mechanisms
Authors: Mair Michael , Bacic Marko , Chakravarthy Kharthik , Williams Ben 
Published: February 2021

Abstract
The switching mechanism and underlying flow physics of an actively controlled fluidic device are investigated using both large eddy simulation (LES) and particle imaging velocimetry (PIV). The fluidic device considered herein uses acoustic excitation of inherent flow instabilities to control the movement of the jet. Acoustic excitation at the preferred frequency is shown to yield high saturation amplitudes resulting in the formation of large vortical structures that do not undergo pairing. Basic flow features including the shear layer instabilities are further examined to explain why the excitation mode that triggers the switching process changes from a shear layer-based mode (Stθ=0.012) to a jet orifice mode (Sth=0.25) as the Reynolds number increases.
Minimizing Numerical Ventilation in Computational Fluid Dynamics Simulations of High-Speed Planning Hulls
Authors: Gray-Stephens Angus , Tezdogan Tahsin , Day Sandy 
Published: February 2021

AbstractNumerical ventilation (NV) is a well-known problem that occurs when the volume of fluid method is used to model vessels with a bow that creates an acute entrance angle with the free surface, as is typical for both planing hulls and yachts. Numerical ventilation may be considered one of the main sources of error in numerical simulations of planning hulls and as such warrants an in-depth analysis. This paper sets out to bring together the available work, as well as performing its own investigation into the problem to develop a better understanding of numerical ventilation and present alternate solutions. Additionally, the success and impact of different approaches are presented in an attempt to help other researchers avoid and correct for numerical ventilation. Interface smearing caused by the simulation being unable to track the free surface is identified as the main source of numerical ventilation. This originates from the interface between the volume mesh and the prism layer mesh. This study investigates this interface, presenting a novel solution to prism layer meshing that was found to minimize numerical ventilation. Through the implementation of a modified high-resolution interface capture (HRIC) scheme and the correct mesh refinements, it is possible to minimize the impact of numerical ventilation to a level that will not affect the results of a simulation and is acceptable for engineering applications.
Experimental Study on Rolling Friction Coefficient Controllability of Magnetorheological Elastomer
Authors: Lian Chenglong , Lee Kwang-Hee , Lee Chul-Hee , Li Yongfeng , Zhang Peng 
Published: February 2021

Abstract
Magnetorheological elastomers (MREs) are smart materials whose stiffness and shear modulus can be changed by applying an external magnetic field. They can be used in various ways. This experimental study looks at the rolling friction coefficient controllability of MREs. MRE samples were manufactured, and their rolling friction properties were measured by a rolling friction test, in which the input magnetic field strengths and rolling speed can be adjusted. Various speed conditions were applied to find the rolling friction properties under different applied magnetic field strengths. The rolling friction coefficient and slip rate control under a magnetic control were then analyzed. The results show that the rolling friction coefficient can be adjusted at different rolling slip rates by the application of a magnetic field, which can increase the rolling friction coefficient range in the control system of the rolling friction coefficient and slip rate. Based on the results of this research, MREs could someday be used in antilock brake systems as a stiffness-control material when a controlled magnetic field is applied, and the rolling friction efficiency could be increased.
Effect of Heat Flux on Bubble Coalescence Phenomena and Sound Signatures During Pool Boiling
Authors: Negi Akshat , Rishi Aniket M. , Kandlikar Satish G. 
Published: February 2021

Abstract
Boiling heat transfer is extensively used in various industrial applications to efficiently dissipate a large amount of heat by maintaining low surface to fluid temperature differences. The maximum heat flux dissipated during boiling is limited by the critical heat flux (CHF). Difficulties in visualizing the boiling process and monitoring surface temperature make it difficult to identify the impending CHF condition. As a result, larger factors of safety are employed, and the equipment is operated at considerably lower heat fluxes. This study focuses on identifying acoustic signatures of different nucleate boiling regimes. The bubble nucleation and coalescence along with bubble collapse lead to variation in acoustic emission patterns during boiling. In this work, acoustic signatures representative of the impending CHF condition are identified during pool boiling of water over plain and enhanced copper substrates. It was observed that sound was dominant in two frequency regions (400–500 Hz dominant throughout the nucleate boiling, and 100–200 Hz dominant at heat fluxes &gt; 100 W/cm2). However, just before CHF, a sudden drop in amplitude was observed in the high frequency region (400–500 Hz), while the amplitude in low frequency region (100–200 Hz) continued to rise. This combination of the amplitude trend has potential to predict the approaching CHF condition. This is the first study that correlates high-speed images with the acoustic trends at different stages of nucleate boiling and compares experimental frequency with Minnaert frequency for coalescing bubbles.
Feasibility Study on the In-Service Testing Program Plan for Safety-Related Dampers of Advanced Power Reactor-1400
Authors: Kang Shincheul , Park Chan , Lee Kyungho , Lee Sungho 
Published: February 2021

Abstract
In-service testing (IST) program including test and examination has been emphasized to assess the operability of the safety-related components in nuclear power plants. Since the issuance of ASME N511 in 2007 concerning IST for air treatment, heating, ventilating, and air conditioning (HVAC) systems, the IST program plan for those systems should be needed to establish prior to setting up the detailed program. The proper plan can contribute to enhance the effectiveness of allotment of the resources inevitable for implementation of the program and ultimately save operation and maintenance costs. In order to achieve the purposes, this paper presents the methodologies to establish IST program plan for safety-related dampers including their selection process of the dampers to be included in the program and representative template made by applying the methodologies. In addition, the method to identify testing types per damper for part of selected dampers is also provided in this paper.
Extending Relational Data Model to Resolve the Conflicts in Schema Integration of Multiple Databases in Virtual Enterprise
Authors: Ma Z. M. , Zhang W. J. , Li Q. 
Published: February 2021

Abstract
Virtual enterprise is typically one kind of information-based enterprise. The features of information system in virtual enterprise can be generalized as heterogeneous and distributed. Its organization and production management put an essential requirement on information integration. In this paper, we shall discuss the forms of conflict in schema integration of multiple databases in virtual enterprise, and give an approach to resolve the conflicts. In order to implement this approach in relational database, an extended relational data model is proposed and the notion of marked partial value is introduced. Based on this extended data model, some relational operations for data management are defined. A case study is discussed about query processing on relational database with partial values.
Virtual Material Processing (VMP) on the World Wide Web: Cold Rolling
Authors: Mehta Bhavin V. , Gunasekera Jay S. , Banga Rajneesh 
Published: February 2021

Abstract
The primary objective of this research work was the development of an engineering package integrated with the Internet, which will allow the user to perform rolling process simulation in a virtual environment on the World Wide Web (WWW). The package should completely analyze the rolling process, which includes plastic analysis of the rolling process using an enhanced slab method. The slab method is very fast and can provide real-time simulation of the process. The virtual environment was developed using tools like Java, VRML, CGI and HTML and is accessible over the Internet from anywhere in the world. This work is a part of a major ongoing project on Virtual Material Processing (VMP), which includes creation of software packages for other manufacturing processes such as extrusion, forging, drawing and sheet metal forming. The Virtual Material Processing (VMP) environment is hardware and operating system independent and does not require powerful workstations or graphics cards. The simulation runs on a powerful server located at Ohio University, while the input/output (text, graphics, animation) can be viewed and accessed by any computer supporting a web browser.
Free-Form Surface Design in a Virtual Reality Environment
Authors: Dani Tushar , Wang Lin , Gadh Rajit 
Published: February 2021

Abstract
This paper presents an intuitive and easy-to-use Virtual Reality (VR)-based interface for free-form surface modeling. This work represents further enhancements to the VR-based parametric conceptual shape modeler (COVIRDS – COnceptual VIRtual Design System) currently being developed at the I-CARVE LAB at the University of Wisconsin-Madison. The current research utilizes an intuitive voice and hand input interface to allow editing of NURBS based free-form surface models. The editing scheme allows the designer to utilize higher level ‘primitive’ surface features, in deforming the free-form shape. In addition, interactively specified constraints allow constrained re-location of these surface features giving the designer additional flexibility in designing relatively complex free-form models. Preliminary results based on a prototypical implementation show that the VR-based interface allows free-form models to be created and edited in a much more intuitive way than is possible in conventional CAD systems. Future work will focus on improving the modeling capabilities of the system by integration with a conventional solid/surface modeler.
Digital Watermarking for 3D Polygonal Model Based on Wavelet Transform
Authors: Date Hiroaki , Kanai Satoshi , Kishinami Takeshi 
Published: February 2021

Abstract
Recently, much interest is being taken in a method to protect the copyright of digital data and prevent illegal duplication of it. However, in the area of CAD/CAM and CG, there are no effective ways to protect the copyright of the 3D geometric models. As a first step to solve this problem, a new digital watermarking method for 3D polygonal models is introduced in this paper. Watermarking is one of the copyright protection methods where an invisible watermark is secretly embedded into the original data. The proposed watermarking method is based on the wavelet transform (WT) and multi-resolution representation (MRR) of the polygonal model. The watermark can be embedded in the large wavelet coefficient vectors at various resolution levels of the MRR. This makes the embedded watermark imperceptible and invariant to the affine transformation, and also makes the control of the geometric error caused by the watermarking reliable.
A Virtual Verification Environment for the Sequence Control System Using VRML and JAVA
Authors: Kanai Satoshi , Kishinami Takeshi 
Published: February 2021

Abstract
This paper describes a visual simulation tool for reliable off-line development, verification and debugging of the control code of the Programmable Logic Controller (PLC) in the sequence control system. First, we discuss the uniform modeling method of the dynamic behavior of various components in a factory (actuators, sensors, operating panels, etc.) as the object model and state transition model. Then we propose the implementation method of the object model by VRML and JAVA. They enable us to uniformly describe the state-transition and corresponding dynamic behavior of the 3-D geometry of each object model. Moreover, we can use a standard VRML viewer which has the event-driven execution mechanism as a visual simulation tool. The effectiveness of proposed implementation and simulation is confirmed through the case study on the co-simulation of combining the component model with a real PLC.
Application of Digital Mock-ups As Visualization Link for Configuration of Customer Specific Products
Authors: Elspass Wilfried J. , Leonhardt Uwe , Meier Markus 
Published: February 2021

Abstract
The scope of this paper is to discuss the central role of digital mockups as a main visualization and verification tool within the development of customer specific products. Shown with the example of a new machining center the various utilization possibilities of the digital mock-up in the overall development process is discussed. The digital mock-up must be understood as a visualization subset of the digital product, which is supposed to be the most complete digital representation of the real physical product possible. The importance of the digital mock-up within the development of customer specific-products is addressed with respect to the main development stages. Moreover effective tools and data management for the specific customization are presented.