bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modes of Adiabatic and Diabatic Fluid Flow in an Annulus With an Inner Rotating Cylinder
Authors: Kaye Joseph , Elgar E. C. 
Published: January 2022

Abstract
The present report is the first phase of an investigation of those variables which control the rate of heat transfer in the air gap of a rotating electrical machine. This phase of the problem reduces to obtaining a basic understanding of the fluid-flow and heat-flow processes in an annulus, formed by two concentric cylinders, with the inner cylinder rotating and with the outer cylinder stationary. The primary independent variables and effects are, first, the axial velocity of the air through the air gap, which is combined with other variables to form the customary Reynolds number; second, the speed of rotation, which is combined with other variables to form a new dimensionless group, called the Taylor number, in honor of G. I. Taylor, who laid the theoretical and experimental foundations for this problem; third, the temperature gradients at the walls; fourth, the surface roughness in the air gap; and finally, the “entrance effects” introduced by the development of the boundary-layer flow in the air gap.
The present report gives the experimental results obtained for two smooth and long annuli, thereby eliminating from consideration, at present, the last two effects given above. It is shown that four distinct modes of flow exist for adiabatic and diabatic flow of air in these annuli. The demarcation lines of these flow regions were investigated in detail for adiabatic flow with hot-wire anemometers and also by means of visual and photographic methods.
The results showed that four modes of flow exist over regions of Reynolds number and Taylor number for both adiabatic and diabatic flow. These modes are: 1 purely laminar flow; 2 laminar flow plus Taylor vortexes; 3 purely turbulent flow; 4 turbulent flow plus vortexes.
The results obtained here for adiabatic flow were found to agree well with the work of Cornish for the boundary line between the regions of laminar flow and laminar-plus-vortexes flow, but they did not agree with similar results by Fage.
Preliminary results are also presented here for diabatic flow in the annulus in the form of heat-transfer coefficients. These results are shown in the form of a three-dimensional surface in which the Nusselt number is represented as a function of the Reynolds number and Taylor number.
Stall Propagation in a Cascade of Airfoils
Authors: Stenning A. H. , Kriebel A. R. 
Published: January 2022

Abstract
A small perturbation analysis of rotating stall is presented which includes the effects of finite pressure rise across the cascade, finite blade chord, and boundary-layer time delay. The theory yields a stability criterion for the initiation of rotating stall, upper and lower boundaries for the velocity of propagation, and a possible explanation for the mechanism governing the number of stall cells. Tests on rotating stall in a cascade and two rotors suggested a vortex-shedding model for fully developed rotating stall which is not limited to small perturbations and which appears to agree closely with the observed stalling mechanism.
The Variable Fluid-Property Problem in Free Convection
Authors: Sparrow E. M. , Gregg J. L. 
Published: January 2022

Abstract
An analysis is made for the variable fluid-property problem for laminar free convection on an isothermal vertical flat plate. For a number of specific cases, solutions of the boundary-layer equations appropriate to the variable-property situation were carried out for gases and for liquid mercury. Utilizing these findings, a simple and accurate shorthand procedure is presented for calculating free-convection heat transfer under variable-property conditions. This calculation method is well established in the heat-transfer field. It involves the use of results which have been derived for constant-property fluids, and of a set of rules (called reference temperatures) for extending these constant-property results to variable-property situations. For gases, the constant-property heat-transfer results are generalized to the variable property situation by replacing β (expansion coefficient) by 1/T∞ and evaluating the other properties at Tr = Tw − 0.38(Tw − T∞). For liquid mercury, the generalization may be accomplished by evaluating all the properties (including β) at this same Tr. It is worth while noting that, for these fluids, the film temperature (with β = 1/T∞ for gases) appears to serve as an adequate reference temperature for most applications. Results are also presented for boundary-layer thickness and velocity parameters.
Vibration of Rods Induced by Water in Parallel Flow
Authors: Burgreen D. , Byrnes J. J. , Benforado D. M. 
Published: January 2022

Abstract
An experimental determination was made of the type and magnitude of vibration in the simulated fuel rods of a heterogeneous nuclear reactor with water flowing parallel to the rod axes. Triangular lattices with equivalent hydraulic diameters of 0.0708, 0.198, and 0.470 ft were studied at a single rod length. The test rods employed had a range of natural frequencies of vibration in water of 5 to 25 cycles per sec. This range was obtained by using ½ and ⅝-in-diam rods made of brass or aluminum, by making some rods hollow and others solid, and by using fixed and pin-ended support conditions. The water velocity was varied from 6 to 21 fps, at room temperature. It was found that the vibration can be significant for reactor conditions. The rod vibration was observed to be self-excited, resulting in the rods vibrating at their natural frequencies independent of the water velocity. A theoretical study of the forces acting on the rods was made from which it appears that ten variables (of which six were varied in these tests) influence the amplitude of vibration of the rod. A correlation was derived and the resulting equations give a good fit with the test data.
The Chatter of Lathe Tools Under Orthogonal Cutting Conditions
Authors: Tobias S. A. , Fishwick W. 
Published: January 2022

Abstract
A mathematical theory of the chatter of lathe tools is presented. Two types of chatter are distinguished depending on whether the chatter amplitudes fall in the direction of the tool shank or in the direction of the workpiece velocity. The physical causes of chatter taken into consideration are the chip-thickness-variation effect, the penetration effect, and the slope of the cutting-force against cutting-speed curve. The results of the mathematical theory are presented in the form of stability charts. With these, chatter arising during the first revolution of the workpiece and that occurring during subsequent revolutions are discussed. It is shown that the stability of the system is affected by the workpiece velocity, the workpiece material, the geometrical shape of the tool and the tool shank, and so on, and that under certain conditions, the chip-thickness variation may have a stabilizing influence. The paper deals only with the effect of the various parameters on the stability conditions and is not concerned with the problem which types of chatter do actually occur in practice.
Experiments on Imperfect Lubrication
Authors: Hersey M. D. , Staples C. W. 
Published: January 2022

Abstract
This brief paper is based upon a full report of certain experiments conducted for the ASME Research Committee on Lubrication. The experimental work comprised friction measurements under imperfect lubrication conditions up to loads of 10,000 psi or more. Eight lubricants were compared whose viscosity-pressure characteristics were known. A Kingsbury oil-testing machine was used, with bearing surfaces designed to eliminate hydrodynamic action so far as possible.
A condition of mixed lubrication prevailed, in which rapid wear of brass on steel occurred simultaneously with hydrodynamic effects. All tests were run well to the left of the familiar minimum point on the coefficient-of-friction diagram. Three methods of plotting the data were tried: (a) The direct plot of friction per unit area against load per unit area, holding the speed and viscosity constant; (b) a conventional plot of the coefficient against Z1N/P, where Z1 is the viscosity at atmospheric pressure, N the speed, and P the load per unit of projected area; and (c) a modified diagram in which each of the foregoing curves is replaced by a family of curves with different values of the pressure-viscosity parameter. This parameter, the product of load per unit area by the pressure coefficient of viscosity, helps to explain earlier discrepancies and to set up a better correlation.
The usual contrast between friction of fatty and mineral oils was confirmed, and it was concluded that boundary lubrication and wear are accompanied by hydrodynamic action on a microscopic scale.
Cavitation and Nuclei
Authors: Knapp Robert T. 
Published: January 2022

Abstract
Contrary to the general impression, water and other common liquids, when pure, have high tensile strength. Cavitation would be impossible at the highest velocities currently encountered. In practice all liquids appear to cavitate as soon as the pressure tends to drop below the vapor pressure, thus implying that liquids have no tensile strength. This discrepancy is explained by the presence of “weak spots” whose characteristics have as yet only been inferred.
This paper presents the results of an experimental investigation of the weak spots present in ordinary water. The results are consistent with the model of the nucleus proposed by Harvey, but are apparently inconsistent with other models currently found in the literature.
After summarizing the results of the experimental program, the paper concludes with a series of implications concerning the engineering significance of the nuclei in industrial liquids.
An Investigation of Effective Thermal Conductivities of Powders in Various Gases
Authors: Deissler R. G. , Boegli J. S. 
Published: January 2022

Abstract
An experimental study was made to determine the effective thermal conductivities of magnesium oxide, stainless steel, and uranium oxide powders in various gases. The gases included air, helium, argon, nitrogen, neon, and various mixtures of these gases. The variables investigated included temperature level, gas pressure, porosity, gas conductivity, and solid conductivity. A reasonably good correlation of the data was obtained by using the dimensionless groups effective thermal conductivity over gas conductivity, solid conductivity over gas conductivity, and porosity of the powder, although the effective conductivity may also be a function of the shape and arrangement of the particles. A solution for spheres in cubical array was obtained by relaxation and was in reasonable agreement with the data for porosities in the neighborhood of that for the spheres.
Oil-Whip Resonance
Authors: Hull E. H. 
Published: January 2022

Abstract
A series of oil-whip resonances has been demonstrated by applying a rotating force to a shaft running in a hydrodynamically lubricated bearing. These resonances appear at the ratios of shaft speed to exciting-force frequency of approximately 2 which is normal oil whip, 3, 4, 6, 8 …. and −2, −4, −6 … . The locus of the shaft center at these resonances traces a trochoid containing a number of loops related to the ratio of shaft speed and force frequency. Inside loops are formed at positive frequency ratios, outside loops at negative ratios. A qualitative explanation of the formation of these resonance figures is offered.
Possible Similarity Solutions of the Laminar, Incompressible, Boundary-Layer Equations
Authors: Hansen A. G. 
Published: January 2022

Abstract
A review of research on the problem of obtaining similarity solutions of the three-dimensional, laminar, incompressible, boundary-layer equations is presented along with a general method of analysis for treating the problem. Restrictions on main flow velocity components and co-ordinate systems which lead to similarity solutions are tabulated. Finally, a discussion is given of the practical application of similarity solutions and the problems which remain to be solved.
Application of the Griffith-Irwin Theory of Crack Propagation to the Bursting Behavior of Disks, Including Analytical and Experimental Studies
Authors: Winne D. H. , Wundt B. M. 
Published: January 2022

Abstract
This paper presents the results of bursting tests of large, bored, and effectively notched disks removed from long rotor forgings. Most of the tests were conducted at room temperature. For the particular disk geometry employed, the net average tangential stress at bursting speed was as low as 25,000 psi for brittle behaving materials and as high as 77,000 psi for materials approaching ductile behavior. These correspond to 26 per cent and 92 per cent of yield strength, respectively. The Griffith-Irwin theory of crack propagation is adapted to the calculation of Gc, fracture toughness, from notched-disk bursting-test results. It is shown that Gc from disk tests agrees with Gc obtained from slow notched-bend tests, and therefore appears to be a property of material, largely independent of specimen size. The actual magnitude of Gc permits the classification of forgings by the degree of their susceptibility to brittle fracture in the presence of discontinuities. Gc and the ratio Kys of room temperature bursting strength to yield strength are found to correlate well with the material Charpy V-notch fracture appearance transition temperature. As the latter is reduced, Gc and Kys are increased.
An Indirect Method for Determining Accelerations in Complex Mechanisms
Authors: Goodman Thomas P. 
Published: January 2022

Abstract
In complex mechanisms such as the six-bar, two-pivot linkage (Fig. 2) the graphical construction for determining accelerations can be simplified by starting from a point on the mechanism other than the point whose acceleration is known. Arbitrary values of velocity and acceleration can be assumed for the starting point, and the accelerations of other points can be obtained graphically on the basis of this arbitrary assumption. The accelerations so found can be converted into the actual accelerations in the mechanism by means of a simple formula which is derived in the paper.
This indirect method of determining accelerations facilitates the analysis of compound mechanisms which consist of two or more mechanisms connected in series. The method also provides a useful check on values of accelerations which have been obtained by other methods.
Three-Dimensional Laminar Boundary Layer in Curved Channel With Acceleration
Authors: Senoo Yasutoshi 
Published: January 2022

Abstract
A theory is developed for two families of three-dimensional laminar boundary layers; namely, for the boundary layer on the plane end wall of a concentric circular-arc channel having a particular family of accelerated or decelerated main flows and for the boundary layer on the parallel plane end walls of a curved channel with logarithmic spiral side walls. A turbine nozzle was approximated by a channel with logarithmic spiral side walls for analysis, and the theoretical prediction of boundary layer on the end wall was compared with the experimental data with fair agreement across the nozzle and along the center line of the nozzle.
Well Trajectory Optimization With an Emphasis on Anticollision Design
Authors: Cao Jie , Wiktorski Ekaterina , Sui Dan 
Published: January 2022

AbstractWell trajectory design and optimization are essential parts in well planning before drilling. The main objective of the design is to find an optimal trajectory for efficient and safe drilling. Meanwhile, the anticollision of well trajectory must be considered with offset wells in the same area. In general, optimal wellbore trajectory design includes some essential criteria, for example, shortest possible path, minimum tortuosity, collision avoidance, and most extended possible contact with the reservoir. This article presents a central part of plan phase represented by a trajectory planning and optimization module with a focus on anticollision design. The trajectory is optimized based either on minimization of wellbore length and dogleg severity or on the maximization of well-reservoir contact subject to strict anticollision constraint and other associated constraints or their combinations to some extent. The anticollision model considers industry standard bit error sources and their interactions and propagation along the well trajectory, and results in the separation factor as an constraint for trajectory optimization. The introduction of anticollision models to the trajectory optimization techniques has real potential in drilling design. Besides saving time and effort by providing engineers with multiple options, the well design with anticollision considerations ensures the well path safety while searching for optimal well trajectory. The presented work has a good potential in well planning as a viable method to keep drilling operations’ safe and efficient.
Analysis of Measured and Predicted Turbine Maps From Start-Up to Design Point
Authors: Scotti del Greco Alberto , Biagiotti Sara , Michelassi Vittorio , Jurek Tomasz , Di Benedetto Daniele , Francini Stefano , Marconcini Michele 
Published: January 2022

Abstract
This paper describes a coupled experimental and computational fluid dynamics (CFD) campaign conducted on a 1.5 intermediate turbine stage in the full range of operating conditions, from start-up to design point under variable expansion ratio and physical speed. The test maintains engine similitude conditions and allows direct comparison with CFD data to assess the predictions accuracy. The choice of variables to describe the speedlines is also addressed by using both measured and predicted data. A discussion on velocity ratio versus corrected speed illustrates the advantages of the former parameter the adoption of which produces constant shape curves in a very wide range of operating conditions. The comparison between measurements and predictions suggests that CFD, in conjunction with performance correlations, is a viable tool to predict speedlines in a fairly wide range of conditions, provided that geometrical and operational details are carefully matched.
Simultaneously Eliminate Defects and Modify Surface for 3D Printed Components Using Femtosecond Laser
Authors: Li Shang , Yang Can , Yang Huan , Peng Fei , Yin Xiao-Hong 
Published: January 2022

Abstract
In this work, the femtosecond laser was used to process the surface of the 3D printed components. After femtosecond laser scanning, the scanning electron microscope (SEM) was utilized to observe the surface morphology of the samples. In addition, the laser confocal microscope (LCM) was adopted to measure the surface roughness, and the contact angle measuring instrument was employed to characterize the surface wettability. By adjusting two laser process parameters (i.e., the number of scan and scan pitch), the surface defects had been successfully eliminated and surface modification for certain application had been achieved. After laser processing, the surface roughness increases to a certain extent due to the generation of surface micro/nanostructures. Wettability experiments showed that compared with the superhydrophilicity of the original surface, the surface contact angle after laser processing increased to a certain extent, and the surface wettability had been changed. In summary, the feasibility of femtosecond laser processing for the surface of 3D printed specimens was preliminarily verified. In the future efforts, multi-parameter experiments and numerical simulation will be further carried out to achieve better post-processing effects for the 3D printed component surfaces.
Effects of Nozzle Diameter and Injection Volume of Drug on Performance of a Needle-Free Injector
Authors: Zhu Yang , Kang Can , Zhang Chunli , Li Haifei 
Published: January 2022

Abstract
Among the techniques of subcutaneous drug delivery, the needle-free injection is relatively new. Compared to the hypodermic syringe, the needle-free injection avoids accidental stabbing and cross-infection. Although the needle-free injection technique has been exercised, the knowledge about instantaneous behaviors of the drug during the injection process have not been clarified. The present study aims to reveal drug flow characteristics of the needle-free injection. The effects of major operating parameters were investigated. An experimental work incorporating the measurement of instantaneous stagnation pressure and the visualization of drug diffusion in gel was conducted. The results show that the needle-free injection process is characterized by time-varying stagnation pressure. The peak stagnation pressure at the initial stage of injection is an important indicator of the aggressivity of the drug. The peak stagnation pressure decreases linearly with the increase of the nozzle diameter or the volume of injection. It is evidenced that the increase in the volume of injection causes an enlargement of the diffusion area of the liquid in the gel, which implies that the drug absorption rate is improved accordingly. Furthermore, with large nozzle diameter, the amount of the power consumed is high. Therefore, the maximum penetration depth of the liquid in gel increases with the nozzle diameter. However, the attainable lateral distance of the liquid is nearly insensitive to the nozzle diameter.
Scaled Crash Testing Using Modeling, Similitude, and Experimentation
Authors: Melnyk Richard , Beattie Olivia , Waller Bogue 
Published: January 2022

Abstract
Due to the complexity and challenging nature of predicting the effects of impact on a vehicle, much of the crash-testing industry remains one which operates at full-scale. Automobiles and even aircraft are often crashed at full size, which is an expensive and time-consuming process. This paper details a novel approach to crash-testing that combines early use of simulation, scaling of the appropriate parameters using similitude, and limited testing. The method was used to predict the crashworthiness of a small, commercial unmanned aerial vehicle (UAV).
The authors were involved in an undergraduate design project to develop a system capable of safely decelerating the RQ-7 Shadow Unmanned Aerial System (UAS) from an operational flight without the use of a runway. For contingency reasons or tactical purposes, the use of a larger runway for the UAS was not feasible. The team developed an airbag-like system that used controlled release of air to decelerate the vehicle. However, due to testing constraints the team was unable to test the airbag system at full-scale with an actual RQ-7 vehicle. The system is already far in it’s life-cycle so there were no prototypes available and the team’s available facilities would not facilitate a large, high-speed test.
As a result, the team built a model of the existing vehicle, focusing on key components and materials. The team then conducted testing at both geometric and dynamic scale and used the results of those tests to determine if actual loading would potentially damage the vehicle. The paper demonstrates the utility of such an approach using the RQ-7 case study.
Key aspects of the approach were the use of a model of the vehicle to determine the likely loading conditions that would lead to material failure. An analysis of the important scaling characteristics was conducted and a novel, non-dimensional ratio was developed. Scaled testing was conducted using instrumentation to determine the unknown scaling parameters. The results were then compared to the actual vehicle through the use of the non-dimensional ratio. The ratio compared the size, the approach speed, and the mass of the model to the actual air vehicle with the ultimate goal of determining whether the decelerations experienced by the model when impacting the airbag, would result in damage to key components on the vehicle when decelerated at full-scale. Testing showed that the model airbag was capable of adequately decelerating the UAV, although improvements needed to be made for greater reliability.