bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Modeling Study of Sand Transport in Slightly Upward Inclined Solid-Liquid Flow
Authors: Vieira Ronald E. , Shirazi Siamack A. 
Published: September 2022

Abstract
Solid transport in inclined pipes is widely encountered in industrial operations, such as oil and gas production and mining. Understanding the mechanism of solid transport in inclined flow lines has significant importance for the development of these practical applications as well as productivity and safety issues. This paper presents an experimental investigation on the hydraulic transport of solid particles in pipelines in a 5° upward inclined orientation. The pipe had an internal diameter of 2-inch (50.8 mm). Water-solid flows which comprised sand (25–600 μm) and water were tested at solids concentrations between 0.01%–0.5% volume-to-volume ratio (v/v). The tests were carried out by observing the movement of the sand particles in a transparent pipe while regulating the flow rate of the fluid. The critical transport velocity (VC) was determined using video recordings. VC was observed to increase with an increase in sand concentration and sand particle diameter. The critical velocities obtained are compared with results obtained from previous experimental work in inclined and horizontal flow and existing modeling approaches available in the literature.
Effects of Throttling Orifice Plate on Flow and Aerodynamic Noise Characteristics Inside Valve Downstream
Authors: Yu Long-jie , Xiang Fang-na , Hao Jiao-shan , Jiang Yong-bing , Jin Zhi-jiang , Qian Jin-yuan 
Published: September 2022

Abstract
The serious aerodynamic noise is caused in the downstream of control valve by high pressure difference. Severe aerodynamic noise will affect worker safety and production safety. Throttling orifice plate located in control valve downstream is one of the most important devices for reducing aerodynamic noise under high pressure difference. Therefore, studying the effect of throttling orifice plate structure parameters on flow characteristics and aerodynamic noise is of great significance. Based on method of computational fluid dynamics, the inclination angle of conical throttling orifice plate is studied as the research variables. The time-average values of the flow field, pressure and velocity are obtained and evaluated through steady-state RANS. Flow rate is evaluated under condition that the throttling area of the plate remains unchanged. Based on the results of steady-state simulation, the aerodynamic acoustic power level in the whole flow field is obtained through the broadband noise source model. Finally, the influence of the plate inclination angle on the aerodynamic noise is comprehensively evaluated. It is concluded that the downward setting orifice plate (45°) is the best among the all orifice plates. The work has a certain reference value for researching the design of throttling orifice plate and improving aerodynamic noise in downstream of high pressure valve.
Cleaning Effect of Bubbles Impacting Tilted Walls Under Acoustic Waves
Authors: Hooshanginejad Alireza , Sheppard Timothy J. , Manyalla Janeth , Jaicks John , Jung Sunghwan 
Published: September 2022

Abstract
The motion of bubbles near walls is ubiquitous for cleaning purposes in natural and industrial systems. Shear stress induced by bubbles on the surface is used to remove particles or bacteria adhering to the surface. In this study, we investigate the cleaning effect of bubbles on a surface coated with a protein soil solution with and without the presence of an acoustic wave transducer at a single frequency. In addition, we test different drying times for the coated surfaces before conducting the cleaning tests. Our results show that the best bubble cleaning effect occurs for the shortest drying time of the coating and an acoustic wave of 100 Hz.
Wall Roughness Effects on Turbulent Flow Past a Near-Wall Square Cylinder
Authors: Chalmers Heath , Fang Xingjun , Tachie Mark F. 
Published: September 2022

Abstract
Separated turbulent flows induced by two-dimensional square cylinder with different gap heights from a solid wall submerged in a thick turbulent boundary layer are investigated using a time-resolved particle image velocimetry system. Two different upstream wall conditions are implemented to investigate the effects of upstream wall roughness on gap flow. The examined gap ratios between the cylinder and the wall include 0.0, 0.5, and 2.0. The incoming Reynolds number based on the cylinder height and freestream velocity is 12, 750 and the boundary layer thicknesses are 3.6 and 7.2 times the step height, respectively, for the smooth and rough upstream wall conditions. The results are presented in terms of mean flow, Reynolds stresses, and proper orthogonal decomposition. Notably, the wall-roughness effects are most pronounced on the vertical Reynolds stresses and act to reduce the vortex shedding frequency.
Field Predictions of Hypersonic Cones Using Physics-Informed Neural Networks
Authors: Villanueva Daniel , Paez Brandon , Rodriguez Arturo , Chattopadhyay Ashesh , Kotteda V. M. Krushnarao , Baez Rafael , Perez Jose , Terrazas Jose , Kumar Vinod 
Published: September 2022

Abstract
Physics Informed Neural Networks (PINNs) provide a way to apply deep learning to train a network using data and governing differential equations that control the physical behavior of a system. In this text, we propose using the PINNs framework to solve an inverse problem which will discover the partial differential equations for compressible flow from Mach number = 5 by coupling Navier Stokes Equations with a Deep Neural Network (DNN) based on training data generated by a CFD solver. The equations of momentum in 2-dimensions and the equation of energy will be parametrized to let Neural Networks calculate two established learnable parameters. This paper will focus on capturing physics governed by fluid flow phenomena applied to high-speed flows using PINNs, which will allow us to see disturbances such as a shock wave interaction with the free stream. Subsequently, a quantification of the predicted results of PINNs will be carried out, and it will be determined if PINNs are computationally less expensive than the Spectral Element Method codes so widely used.
CFD Analysis of a Grooved Heat Pipe for Space Application
Authors: Hemayet Uddin Salman , Islam Md. , Mone Shital , Jarrar Firas , Fernandes Ryan , Fatt Yap 
Published: September 2022

Abstract
Heat dissipation in space applications is very much necessary. For example, a satellite works under an extreme temperature environment depending on the satellite’s position in the orbit. Apart from thermal energy from the sun, the electronic component in the satellite itself generates heat as well. To maintain the temperature of the components within their operational range, a grooved heat pipe (GHP) is one of the best solutions. Within GHP, capillary action plays a major role to transfer the liquid from the condenser side to the evaporator side under a near-zero gravitational environment.
This paper focuses on the numerical simulation of heat and mass transfer in GHP for space application. The Computational Fluid Dynamics (CFD) simulation is performed using Ansys Fluent software. The omega-shaped axial micro-channelled GHP made from aluminium is considered for this study. The working fluid in the heat pipe is ammonia. The volume-of-fluid (VOF) multiphase model along with the Lee model equation is used to perform the mass transfer prediction. The effects of different heat load for a 25% filling ratio (FR) are studied. This paper mainly focuses on the fluid flow development in the initial 40s of the GHP operation for a specified percentage of FR and heat load.
The CFD simulations give much more insights of the heat and mass transfer phenomena, which would not possible to obtain by experimentation. The results like pressure, velocity, temperature, and volume fraction profiles inside the GHP along the length were studied.
Slurry Pumps Instability Investigation Using High Fidelity CFD Simulation
Authors: Garman Mohamed , Visintainer Robert 
Published: September 2022

Abstract
Slurry pumps are widely used in a variety of applications in the mining, dredging, and aggregate industries. Ensuring stable operation is a major task during pump operation.
In the current study, two slurry pumps are compared which differ only in the design of their casing hydraulics, both using the same exact impeller. The test results showed that a severe instability was formed in the head curve when the smaller casing was used which persisted over a large portion of the curve and resulted in a much lower operating efficiency. changing to the larger casing eliminated the instability and restored the expected pump efficiency. In order to investigate the root cause by examining the underlying flow patterns, a high fidelity, transient, full machine model, including impeller side gap, was developed and applied in a flow range from about 110% to 30% of the pump best efficiency flowrate or QBEP. The CFD simulation results were in good agreement with the measured performances, detecting the instability at the same flow rate for the smaller casing, and no instability when the larger casing is used. Surprisingly, considerable difference between the models appears within the impeller passages, even though its hydraulic design did not change. These differences are characterized, some theories offered regarding the underlying physical effects, and design guidelines proposed for avoiding the undesirable instability in future designs.
Numerical Analysis of Dielectrophoretic-Based DNA Separation and Trapping
Authors: Darabi Jeff 
Published: September 2022

Abstract
In this study, dielectrophoresis (DEP) has been coupled with field-flow fractionation (FFF) for the sorting and trapping of the biological particles. A numerical simulation is performed to compute particle trajectories under the influence of DEP, drag, gravitational, and buoyancy forces, as well as Brownian motion. The simulation was performed using OpenFOAM CFD software. Both positive and negative DEP methods are examined as possible separation techniques for DNA fragments. Positive DEP forces are used to attract the particles to the electrodes and trap them in groups of similar particles while a combination of negative DEP forces and field flow fractionation (FFF) are used to levitate the particles within the fluid flow to certain flow trajectories. The results obtained from this study, including electric field simulations, particle trajectories, elution times, and trapping lengths are presented.
Onto Quantifying Unsteady Propulsion Characteristics Using Momentum and Energy Control Volume Assessments
Authors: Loubimov George , Kinzel Michael 
Published: September 2022

Abstract
This work proposes a novel approach to characterize unsteady, undulating propulsion components through evaluating the momentum and energy equations using detailed control volume analyses. Specifically, it is difficult in such conditions to separate thrust from drag as pressure components are inseparable. In general, the goal is to link physical processes to various components in the control volume assessments that are measurable in detailed computational fluid dynamics (CFD) models. The effort utilizes the Method of Manufactured Solutions (MMS) to verify detailed insight can be extracted from the control volume assessments are developed and indicate that the energy equation uniquely highlights lift-work in the energy budget and separating propulsive and drag forces. The effort expands the findings to previously validated CFD studies studying thrust from heaving and pitching foils; results indicate a novel approach to separate the axial force into thrust and drag components. Overall, the results indicate a promising method useful to separate losses from propulsive mechanisms along with novel metrics of efficiencies useful to measuring self-propelling vehicles.
Experimental Study on Heat Transfer Performance and Flow Pattern in Micro-Fin Tubes and 1EHT Three-Dimensional Heat Exchange Tubes
Authors: Cheng Hong , Gao Yu , Li Wei , Kukulka David John 
Published: September 2022

Abstract
Condensation heat transfer characteristics were studied experimentally using R410A for a mass flow range of 250∼450 kg m-2 s-1 and saturation temperature of 45°C in order to determine the performance of smooth and enhanced heat transfer tubes. Visual flow patterns under condensation conditions were observed in horizontal tubes. Smooth tube condensation flow patterns are consistent with the predicted flow patterns from previous investigations and heat transfer performance in enhanced tubes were compared with the performance found in smooth tubes. The condensation heat transfer enhancement ratio for the enhanced tubes are: 1.15∼2.05 (Vipertex model 1EHT tube), and 1.18∼1.69 for a Helix tube (HX) tube. In addition, the material thermal conductivity of a smooth tube has a small influence on its heat transfer performance; greater enhancement was found in the enhanced tubes. Stratified wavy flow (SW), intermittent flow (I), semi-annular flow (SA) and annular flow (A) were observed in the range evaluated.
The heat transfer coefficient increases with an increase of mass velocity. When the mass flow rate increases, the turbulence of the liquid flow increases and the liquid film becomes thinner. This reduces the thermal resistance and enhances heat transfer; heat transfer performance for low mass velocities rise slowly. The performance improvement at high mass flux rates is greater than that at low mass flux rates. Better heat transfer performance is shown for tube wall materials with high thermal conductivity and/or tubes with smaller diameters.
On the Transition Between Re-Entrant Jet and Condensation Shock Mechanism in Sheet to Cloud Cavitation
Authors: Vaca-Revelo Diego , Gnanaskandan Aswin 
Published: September 2022

Abstract
Sheet to cloud cavitation over a wedge is investigated using numerical simulations performed at a Reynolds number Re = 200,000 and cavitation numbers ranging from σ = 1.44 to σ = 2.18. The multiphase fluid is described using a homogeneous mixture model, and the governing equations are the compressible Navier Stokes equations for the liquid/vapor mixture along with a transport equation for the vapor mass fraction. The numerical method, based on a characteristic based filtering approach for shock and interface capturing, is first validated by comparing with the experimental measurements, showing acceptable agreement. A systematic parametric investigation of sheet to cloud cavitation phenomenon for different cavitation numbers is then carried out. The two primary mechanisms known to destabilize the sheet cavity viz. the re-entrant jet mechanism and the condensation shock mechanism are captured in the simulations. Two cases in the condensation shock regime and two cases in the re-entrant jet regime are investigated in this paper; the similarities and differences between the two regimes are elucidated. The results presented here are part of an ongoing investigation on identifying the precise physical conditions that lead to the transition between the re-entrant jet and condensation shock mechanisms, a clear knowledge of which is yet to be elucidated.
Internal Flow of Sessile Droplets Evaporating on Heated Hydrophobic and Superhydropholic Substrates
Authors: Chen Jingbo , Pan Zhenhai , Wang Zhiguo , Cao Jun , Du Wen , Yu Jialing 
Published: September 2022

Abstract
Evaporation of sessile droplet is a significant common phenomenon. A three-dimensional numerical analysis was carried out to investigate the flow structure inside the sessile evaporating droplet. The present model developed in this study takes buoyancy, vapor diffusion, and evaporation cooling into account. Different flow structures are present inside the droplet evaporating on the hydrophobic and super hydrophobic substrates. On the hydrophobic substrate, the axisymmetric vortex appears in the droplet. The fluid at the bottom of the droplet flows upward along the axis direction, and then flows downward along the droplet surface. On the super hydrophobic substrate, a single non-axis-symmetric vortex is present inside the droplet, the fluid at the bottom of the droplet flows upward along one side of the droplet surface and downward along the other side. The influence of droplet volume and substrate temperature on the flow velocity and temperature distribution inside droplets is discussed quantitatively. The origin of the non-axisymmetric Raleigh convection inside the droplet on the heated superhydrophobic substrate is discussed. We found that the axis-symmetric flow in the droplet is not stable on heated superhydrophobic substrate. Any perturbation in the system can get enlarged and drive the instable axis-symmetric flow turns to a non-axis-symmetric rolling flow.
Separation Control on an NACA 0025 Airfoil Using an Array of MEMS-Based Synthetic Jets
Authors: Xu K. , Lavoie P. , Sullivan P. 
Published: September 2022

Abstract
An novel array of micro-electromechanical systems (MEMS) synthetic jets was designed to control flow separation by periodic blowing at two pre-determined frequencies on a NACA 0025 airfoil for a chord Reynolds number Rec = 105 and angle-of-attach α = 10°. The synthetic jets were generated by commercially available microblowers, providing ease of maintenance compared to other customized synthetic jet actuators. The velocity output of this jet array was characterized with hot-wire anemometry (HWA), and reattached flow was identified using smoke-wire visualization. Pressure measurements show that the array can suppress flow separation on the airfoil, resulting in 2.5 times lift recovery. From wake measurements, up to 50% drag reduction was achieved with the actuation of the jet array compared to the baseline (uncontrolled) case. Particle image velocimetry (PIV) was used to visualize the flow fields of the baseline case and two controlled cases. There was a significant difference in the scale of the vortices produced by the jet array and features of the reattached flow between the two actuation frequencies used.
Turbulent Characteristics of the Wake Flow Around Rectangular and Trapezoidal Prisms in Uniform Flow
Authors: Kang Jinhao , Kumahor Sedem , Sagharichi Amir , Tachie Mark F. 
Published: September 2022

Abstract
The turbulent characteristics of flow separation induced by a trapezoidal and two rectangular prisms immersed in a uniform flow were studied experimentally using particle image velocimetry. The streamwise aspect ratios (AR) of the two rectangular prisms were 3 and 4. The streamwise AR of the trapezoidal prism was based on its upper length and was 3. The Reynolds number based on the freestream velocity and the prism height was 14700. The flow topology of symmetrical wake flows over and behind the rectangular prisms and asymmetrical wake flow over and behind the trapezoidal prism were analyzed using the mean flow and Reynolds stresses. The results indicate that the mean flow reattaches onto the rectangular prisms but does not reattach onto the trapezoidal prism. Dual local regions of elevated streamwise Reynolds normal stress occur in the wake region irrespective of AR and the body geometry. However, the dual elevated regions are only symmetric about the horizontal centerline of two rectangular prisms. Probability density function (PDF), two-point correlations and proper orthogonal decomposition (POD) analyses were employed to investigate the dynamics of the coherent structures formed over and behind the prisms.
Investigations of Aspect Ratio Effects on Wake Dynamics of Rectangular Cylinders
Authors: Liu Manqi , Kumahor Sedem , Audette Lucas , Tachie Mark F. 
Published: September 2022

Abstract
In this paper, the flow characteristics around rectangular cylinders with different length to height ratios (aspect ratios, AR) of AR1, AR2, AR3 and AR4 are studied using a particle image velocimetry. The Reynolds number (Re) was 7200 in all cases and the results were analyzed in terms of the mean flow characteristics, Reynolds stresses and triple velocity correlations. The separated flow did not reattach for AR1 and AR2 cylinders. The flow topology around the AR2 cylinder showed a massive wake vortex compared to the other tested cases. The recovery of the mean velocity within the wake region was slowest for AR2, meanwhile, AR3 and AR4 revealed mean reattachment over the cylinder. The magnitudes of the Reynolds stresses and triple velocity correlations were consistently higher along the cylinder centerline for AR1 compared to the other cases.
Four-Way Coupled Simulation of Proppants Flowing in Rock Fracture With Realistic Geometry- Hydraulic Fracturing Application
Authors: Rousta Farid , Ahmadi Goodarz , Crandall Dustin 
Published: September 2022

Abstract
Four-way coupled Lagrangian-Eulerian proppant-laden flow simulations were performed using different software, including Star CCM+ and the Rocky package coupled with the Ansys-Fluent code. The particular application was focused on the hydraulic fracturing process. The uniformity of the proppant distribution and the total proppants coverage inside the rock fracture define the process efficiency. The desired outcome is a high number of particles trapped uniformly inside the fracture providing high fracture coverage. This study simulated the high-pressure liquid-solid mixture flow and predicated proppants’ transport, displacement, and distribution in rock fractures. A realistic three-dimensional rock fracture geometry was generated using the Brown method. Several pressure gradients were considered, and the four-way coupled proppant-laden flows in fractures with various aperture sizes and lengths were simulated. The effects of proppant size, fluid properties, and fracture characteristics on the final coverage were studied. In addition, different horizontal and vertical fracture configurations were considered. It was shown that the fracture coverage changes dramatically by including a realistic surface roughness compared to a smooth channel fracture model. It was also shown that the ratio of particle diameter to the mean aperture size significantly affects the fracture coverage, and the optimum proppant size for a given aperture was evaluated. The number of trapped proppants inside the fracture was tracked over time from the injection until the steady-state flow was reached, and the number of particles approached a constant value. The final steady-state coverages for different cases were calculated and compared. Finally, the influences of various parameters on the efficiency of the fracturing process were discussed.