In this study, a segment of water conveyance system at a chemical manufacturing facility is under investigation. The pipe segment under investigation conveys a daily average flow of five million gallons of water per day (MGD) from the river to a water treatment plant. The exact age of the pipe system is unknown as limited construction or maintenance information exists. The study area is a pipe segment near the treatment plant where three flow restrictions exist within a 30-foot distance bounded by a T-junction and a water filtration plant. These restrictions include two self-actuated butterfly valves and an orifice plate on a 16-inch diameter steel pipe, buried approximately three feet below ground surface. When standing in the study area, heavy vibrations are felt at the ground surface. The valves and orifice plate are to control flowrate and reduce pressure from 80 PSI to 45PSI as the flow enters the water treatment plant. Flow restrictions in close proximity can cause cavitation, water hammer and other flow phenomena within a pipe system. This can result in excessive wear of the pipe’s inner walls and valves which may compromise the structural integrity and/or function of the system. Computational fluid dynamics (CFD) software is a useful tool for determining if the conditions for the various flow phenomena are present in a system. The flow characteristics were numerically calculated in MATLAB then computationally modeled in AFT Fathom. The purpose of the numerical analysis was to describe the stability of the fluid flow at discrete points in the pipe network and identify the network segments with significantly unstable flow profiles. The purpose of the AFT Fathom CFD model purpose was to provide a continuous simulation of the flow stability in the pipe segment and provide a more robust description of the flow profiles in the network. While Fathom cannot explicitly predict cavitation or water hammer, the kinematic parameters produced by the Fathom model and the physical conditions observed in the study indicate that water hammer is likely occurring.

Special mixing chambers are usually used to perform scientific experiments or for routine industrial production processes. This is the case, typically, of fan mixers in a baffled tank. Mixing chambers comprise, among other alternative elements, two counter-rotating fans at the bottom and top. These will eventually allow a mixing effect on the chamber with an adequate level of uniformity. Herein a computational flow simulation is performed for the mixing conditions of air and SO 2 inside the chamber used in the CLOUD experiment, by studying in detail the flow structures and uniformity inside the chamber. This Unsteady Navier-Stokes computation is performed using the kω-SST and SAS turbulence models. A first validation step is performed by using an experimental test case, comprising a T-junction geometry, that performs the mixing of air and N 2 . Following this validation step a detailed analysis of the flow structures inside the 3D chamber is conducted, and specific insights are given regarding the flow uniformity. A detailed analysis of the computed mixing flow structures for the SST and SAS turbulence models is also described. It is shown that the SAS model captures with more detail the macro and meso-mmixing process with an accuracy of, at most, 6%. This value can be further reduced to values around 2% by resorting to high density meshes, with the associated computational burden.

There are several industrial applications in which two phase solid-gas flows are involved. At times, pipe junctions are involved where flow split takes place. Present study consists of experimental investigation of turbulent gas-solid two-phase flow through horizontal pipe junctions. The effects of air flow rate, branch diameter and pipe orientation at junctions are investigated on mass fraction, phase split and solid particles distribution across the junctions. Silica powder, in the monodispersed size of 15 μm was injected into the pipelines by a micro-feeder. The powder was entrained in an air flow which passed horizontally through a long straight channel of circular pipe with T and Y junctions. The main pipe was 51mm in diameter while the inlet superficial velocity of gas was varied from 5 m/s to 13.5m/s. The particles mass concentration was measured by the aerodynamic particle sizer (APS). Experimental results showed that solid phase split followed air flow split while decreasing the inlet air velocity caused major decrease in the mass fraction at junction pipe. The orientation of junction pipe has a significant effect on the flow behavior along the pipe. These results indicate that the behavior of solid particles is a complex phenomenon in pipe flows.

Virtual reality (VR) is becoming increasingly popular in educational applications, but insufficient users’ feel of immersion often slows the further adoption of VR. Many solutions with a focus on the results rather than the details of the interactions between the objects in the real and virtual worlds have been developed. Therefore, the real procedures are distorted and the users lose their perception of in-person participation. In order to improve the users’ feel of immersion further and to simulate more realistic operations in VR, a procedure-oriented approach for the combination of real and virtual environments is proposed here. As its name implies, this approach emphasizes the details of the procedures, namely how to capture, track, operate and interoperate the real and virtual objects in a mixed environment. In order to illustrate this idea, a prototype of mixed real and virtual assembly, in con-junction with object recognition and rigid-object tracking functions based on robotic vision techniques, is presented as an example. This prototype is designed based on a game-based virtual laoratory system, and the specific implementation is a planetary gear train experiment. In this experiment, all models of the parts with the information required for the assembly are created, labeled and added to the database of the virtual laboratory system. The physical parts are marked in order to facilitate object recognition and object tracking. During the experiment, the main assembly with one missing planetary gear is accomplished in a purely virtual environment. In the real world, the missing planetary gear is tracked by a Kinect while the user is manipulating this gear. Then, the system recognizes this gear based on the markers and couples the corresponding virtual model of that gear with the avatar’s hand in the virtual environment. Afterward, the cam-era tracks the real part, and the user can adjust its pose and location to finish the final assembly. The main benefit of this implementation is that the user can take advantage of some simple real parts in conjunction with virtual models of sophisticated parts in order to get realistic experience with the assembly process.

In the clinical application, the mechanical stimulation against the damaged brain tissue is adopted as the kinesitherapy for the nerve regeneration. Nevertheless, the fundamental mechanism to repair the damaged nerve cell has not been revealed yet. Recently, the cyclic stretch stimulation has been reported as the efficacious treatment method to enhance the axonal extension for regenerative therapy of injured nerve cell. Therefore, we try to develop a new cellular automaton (CA) finite element (FE) hybrid method to predict the axonal extension and nerve network generation, which can evaluate the effect of stretch stimulation on the cell body, axon and dendrites. In the FE results, the stress concentration occurred at the junction of the axon and cell body. The maximum stress value in the axon was 8.2 kPa which is about twice as large as that of the cell body. CA adopted to predict the morphological evolution of nerve cells under the mechanical stimulation. It was confirmed that the stress affects to accelerate the axonal extension as experimentally suggested. As a result, our CAFE can be employed to simulate the axonal extension and generation of nerve network system under the condition of extra cellular mechanical stimulation.

Microfluidic applications may involve the control of flows through a series of junctions. For example, flow branching is typically used to deliver specific quantities of fluid to various locations and converging flows are associated with mixing processes. The shape of the fluid interface of the converging flows at and downstream of the flow junction is the focus of this study. In particular, we investigate the transition from planar stratified flow to annular flow. We report results for microchannel configurations which have a main channel and an intersecting (at 90 or 45 degrees) daughter channel. Two 90 degree channels are investigated, one with cross sectional dimensions 129 × 100 um and the other 200 × 100 um. The 45 degree channel dimensions are 161 × 100 um. We compare flows of water over various Reynolds numbers (based on total flow) of 5–400. Flow visualization is achieved using confocal fluorescence microscopy. Flow modules are fabricated using soft lithography techniques and are enclosed by bonding plasma cleaned glass slides to the PDMS module. At lower Reynolds numbers, e.g., < 20, stratified flow is achieved with some curvature at the interface. As the Reynolds number increases, the flow transitions to have large degrees of curvature and eventually into annular flow. This transition is influenced by Reynolds number, flow ratio (daughter/total flow), channel geometry (cross section) and configuration (45 vs. 90 degrees). Flow regime plots are produced for all microchannel configurations. This study should provide insight into intersecting microfluidic flows when the Reynolds number is high enough to produce a non-planar fluid interface at the junction.

We employ molecular dynamics simulations to explore the effect of tensile strain on the thermal conductivity of carbon nanotube (CNT)-graphene junction structures. Two different types of CNT-graphene junctions are simulated; a perfect seamless junction between CNT and graphene with complete sp 2 covalent bonds, and a CNT-graphene junction with mixed sp 2 / sp 3 covalent bonds are studied. The most interesting phenomenon observed in the present research study is that the thermal conductivity of CNT-graphene junction structures increases with an increase in mechanical strain. For the case of CNT-graphene junction structure with pillar height of 50 nm and inter-pillar distance of 15 nm, the thermal conductivity is improved by 22.4% when 0.1 tensile strain is imposed. It is observed that the thermal conductivity improvement is enhanced when a larger graphene floor is placed between junctions since larger graphene floor allows larger deformation (larger tensile strain) in the junction. In addition, the thermal conductivity of CNT-graphene junction structures with pure sp 2 bonds is observed to be higher than the thermal conductivity of CNT-graphene junction structures with mixed sp 2 / sp 3 bonds regardless of the amount of tensile strain. The obtained results will contribute to the development of flexible electronics by providing a theoretical background on the thermal transport of three dimensional carbon nanostructures under deformation.

Due to the high surface area to volume ratios leading to intensified heat and mass transfer rates, microreactors have been subject of interest for some time. Liquid-liquid two-phase flow is a very common phenomenon in microchannels. During the scale-up using a numbering-up approach, rectangular and square microchannels are preferred to circular microchannels in terms of easier integration of the former with a less volume. Therefore, liquid-liquid two-phase flow in non-circular microchannels has been investigated recently. However, there are still gaps in the fundamental understanding of liquid-liquid two-phase flow, such as the effect of inlet junctions or arrangements on flow patterns in non-circular microchannels. The present work aims to study the effect of inlet arrangements on liquid-liquid two-phase flow dynamics and flow patterns of square glass microchannels. In this paper, oil is used as the dispersed phase and de-ionized water is used as the continuous phase. The special inlet arrangement in the cross-junction is compared to these common inlet arrangements of T-junction and cross-junction square microchannels. The effect of the inlet continuous phase velocity on the slug length is studied. Then, the slug lengths with the same inlet velocities of the three inlets and equal velocities of the two phases are carried out, respectively. Meanwhile, typical liquid-liquid flow pattern transitions are achieved at specific conditions. Finally, a special phenomenon without the droplet flow pattern is introduced, due to introduction of the novel inlet arrangement.

The blockage of arteries in the human vertebrobasilar system (VBS) usually results in major disability or death. It has been widely seen that atherosclerotic stenosis occurs at locations with a low wall shear stress or a high oscillatory shear index. This study investigates the potential of developing arteriostenosis due to smoking in the human VBS at 3 different ages. For this purpose, the VBS has been modeled for smoking/nonsmoking subjects that are 20, 50, and 70 years of age. The governing equations were discretized and solved by a finite volume-based software (ANSYS Fluent v15.0). Five potential locations for stenosis were determined along the VBS. The quantified risks of stenosis were found for smoking and nonsmoking groups, indicating that the locations prone to stenosis are at a higher risk in smoking subjects. The stenosis probability increases around vertebrobasilar junction point (VBJ) and along the right vertebral artery in the 50 and 70-year-old smoker subjects, respectively. Also, the results suggested that the area around the VBJ is at higher risk levels for stenosis at different ages for both smoking and nonsmoking subjects.

Modular designs give orthopaedic surgeons a greater flexibility to custom fit the implant to the patients bone while performing total hip arthroplasty. Titanium alloy (Ti6Al4V (ASTM F-136)) is typically used for modular hip implant stems. This highly corrosion resistant alloy forms passive surface oxide films spontaneously. However, with modular designs, micro-motion may occur at the taper junctions during mechanical loading. Crevices between the taper junctions may allow the body fluids to enter and remain stagnant. These conditions make the modular tapers susceptible to fatigue and mechanically assisted crevice corrosion. The in vivo degradation of metal alloy implants compromises the structural integrity. The influence of stress corrosion induced pits of a titanium-alloy modular implant in cement-less total hip arthroplasty was numerically investigated. The effect of pit geometry parameters — cylindrical, conical, and hemispherical dimple are compared and discussed in terms of taper performance.

The transport processes in the mixing of either two gases or two miscible liquids in a T-junction are investigated numerically. Both laminar and turbulent flow fields are considered. The 3-D time-dependent flow fields are calculated for the T-junction (of two circular cross-section pipes that meet orthogonally at the junction). For turbulent flow regimes, the large eddy simulation (LES) technique is employed. In the 3-D mathematical model, the transport of species is described by the species conservation equations. The results obtained by the numerical simulations are verified with available experimental data in the literature for methane-air mixing in a T-junction. The effect of variation of the value of turbulent Schmidt number is investigated. Temporal concentration fluctuations are calculated and are compared to the spatial fluctuations. The mixing of two miscible liquids (water and peracetic acid-water mixture) are also investigated for the laminar and turbulent flow fields (using the LES technique). The mixing behavior of two gases and two miscible liquids in a T-junction are compared and contrasted for both laminar and turbulent flows.

The potential applications of micromixers continues to expand in the bio-sciences area. In particular, passive micromixers that may be used as part of point-of-care (POC) diagnostic testing devices are becoming commonplace and have application in developed, developing, and relatively undeveloped locales. Characterizing and improving mixing efficiency in these devices is an ongoing research effort. Micromixers are used in some lab-on-chip (LOC) devices where it is often necessary to combine two or more fluids into a mixed solution for testing or delivery. The simplest micromixer incorporates a tee junction to combine two fluid species in anti-parallel branches, with the mixed fluid leaving in a branch perpendicular to the incoming branches. Micromixers rely on two modes of mixing: chaotic advection and molecular diffusion. In micro-mixers flow is typically laminar, making chaotic advection occur only via induced secondary flows. Hence, micromixers, unless carefully designed, rely almost exclusively on molecular diffusion of fluid species. A well designed micromixer should exhibit significant chaotic advection; which is also a sign of large strain rates and large entropy generation rates. This paper describes the development of an analytical relationship for the entropy generation rate and the mixing efficiency as function of the outgoing branch Reynolds number. Though there has been extensive research on tee junctions, entropy generation, and the mixing efficiencies of a wide variety of micromixers, a functional relationship for the mixing efficiency and the entropy generation rate has not been established. We hypothesize a positive correlation between the mixing index and the entropy generation rate. The worked described here establishes a method and provides the results for such a relationship. A basic tee junction with square cross sections has been analyzed using computational fluid dynamics to determine the entropy generation rate and outgoing mixing efficiencies for Reynolds numbers ranging from 25–75. The mixing efficiency is determined at a location in the outgoing branch where the effects of molecular diffusive mixing is minimized and chaotic advective mixing is the focus. The entropy generation rate has been determined for the indicated range of Reynolds number and decomposed into its viscous and diffusive entropy terms. The functional relationships that have been developed are applicable for micromixer design and serve as a reference for more complex passive micromixer designs.

Recent advent of Aqueous-Two-Phase-System (ATPS), more biologically friendly compared to conventional oil-water systems, has shown great potential to rapidly generate aqueous droplets without tedious post-processing. However, understanding of underlying physics of droplet formation in ATPS is still in its infancy. In this paper, we investigate hydrodynamic behaviors and mechanisms of all-aqueous droplet formation in two flow-focusing droplet generators. Two incompatible polymers namely polyethylene glycol (PEG) and dextran (DEX) are mixed in water to make ATPS. The influence of inlet pressures and flow-focusing configurations on droplet sizes, and thread breakup length is studied. Flow regime mapping for two different configurations of droplet generators possessing junction angles of 30° and 90° is also obtained. The results show that droplet size is very susceptible to the junction angle while inlet pressures of the PEG and DEX flows readily control four main flow regimes including back flow, dripping, jetting and stratified.

Urine is transported from the kidney to the urinary bladder through the ureter by peristalsis and pressure gradients. The contractile force acting on the ureter wall has drawn considerable interest in the field of biomechanics. Backflow of urine from bladder to the kidney can occur due to failure of the ureterovesical (ureteral-bladder) junction or blockage in the ureter passage because of recurrent urinary tract infection and also due to formation of stone in kidney. To understand the nature of the flow as well as its effect on the ureter wall, two-way fluid-solid interaction (FSI) modeling of the ureter peristaltic flow at different pressure is required. A transient 2D axisymmetric numerical calculation of ureteral wall peristalsis and urine flow is performed with a fully-coupled monolithic solver using an arbitrary Lagrangian-Eulerian (ALE) method. The ureter is assumed to be a circular tube with successive compression waves traveling downstream. The incompressible Navier-Stokes equations are solved to calculate the laminar flow of urine. The ureter wall is modeled as a non-linear hyper-elastic, nearly incompressible material, by curve fitting the biaxial test data of a human ureter, obtained from literature. Displacement due to peristalsis on ureteral wall is created with a compressive force having a Gaussian bell-curve variation along the length of the ureter, and a certain wavelength specified according to the data found from previous studies. It is observed that, as the compression wave travels from the abdominal part of the ureter towards to the pelvis, it is more likely for urine reflux to occur due to the failure of the ureteropelvic junction rather than the ureterovesical junction.

T-sectioned configurations with a deadleg at the stopple are present in natural gas pipelines, where liquid water may accumulate, increasing the potential for internal corrosion. The objectives of the present study are to explore the pipeline operating conditions under which water enters the deadleg and define an operating protocol to prevent water accumulation in deadlegs. A combined computational fluid dynamics (CFD) experimental and analytical study was conducted to understand the behavior of liquid slugs at the T-junctions with dead ends. The flow equations were solved as an unsteady multiphase (gas and water) incompressible flow problem using the Volume of Fluid (VoF) Method. The analytical calculations were based on a modified form of the macroscopic mechanical energy balance equation. In order to computationally simulate the critical velocity at which water enters the deadleg, the inlet gas flow rate was specified to be a fixed value, while the water flow rate was gradually increased. The liquid entirely bypasses the deadleg until the liquid water velocity exceeds a critical value, which was noted as the critical superficial liquid velocity. The experimental study was conducted using a flow loop to understand the behavior of liquid water at the T-junction and determine the condition when liquid enters the deadleg. The analytical and computed solutions were compared with experimental observations. The computed results follow the same pattern as the experimental and analytical data. Solutions indicate that critical superficial liquid velocity is linearly dependent on superficial inlet gas velocity.

Frequently, Two-phase flow occurs in petroleum industry. It takes place on production and transportation of oil and natural gas. Initially, the most common patterns for vertical flow are Bubble, Slug, Churn and Annular Flow. Then, for horizontal flow, the most common patterns are Stratified Smooth, Stratified Wavy, Elongated Bubble, Slug, Annular, Wavy Annular and Dispersed Bubble Flow. It is also known that after separation, each fluid is carried through pipes, so oil is moved long distances. However, as it is known, the oil energy diminishes on the way. For that reason, it is needed a pumping station for keeping the oil flow energy high for proper movement. Additionally, that fluid is transported through a network, so fittings are present, like elbows, “T” and “Y” junctions, and others. As known, on a piping network, the losses can be classified in two groups: large and localized. The former consists on losses due to wall roughness-fluid interaction. The latter is related with fittings. This study is focused on 45° “Y” junctions. The main purpose of this study is to simulate the fluid flow on a 45° “Y” junction, using a 0.1143 m diameter 2 m length pipe, in which a 0.0603 m diameter 1 m length pipe confluences, using oil-gas as the working fluid, considering Dispersed Bubble Pattern. It can be attributed a “K” flow loss coefficient for each path, from each entry to the exit of the junction. For the Two-Phase Flow, it was supposed a horizontal Dispersed Bubble Pattern, which takes place at very high liquid flow rates. So the liquid phase is the continuous phase, in which the gas phase is dispersed as discrete bubbles. Particularly three API Grades were considered for the oil, corresponding to three main types of continuous phase. For the numerical model, it was generated several non-structured grids for validation, using water as a fluid. Then the simulations were carried out, using non-homogenous model, with oil and gas, changing the gas void fraction, and the superficial velocities for gas and liquid. A commercial package was used for numerical calculations. It was encountered that changing the value of the referred variables, in some cases the exit pressure of the “Y” junction diminishes. For validation of the results, a literature model was used for comparing both “K” loss coefficients: numerically and from the bibliography. It is important to highlight that these results, permit to analyze a way of diminishing the fluid energy losses in a Two-Phase oil-gas piping network, particularly in 45° “Y” junctions which represents economically saving.

Skeletal trauma occurs in many blunt, ballistic and blast impact events. Even though the personal body armors and protective equipment were effective in stopping the penetration of bullets or fragments, the resulting impact loading could lead to the significant injuries and fractures to the thoracic skeleton and extremities. The finite element (FEM) method, with its capability to handle complex geometries and nonlinear materials, are commonly used to analyze the tissue biomechanical responses and correlate the simulation results with the injury outcomes. However, it is very difficult to construct the three-dimensional (3D) FEM model for the skeletal biomechanics analysis because of the complex geometry and different materials involved. Moreover the simulation of 3D FEM model is computationally expensive because both small element size and high speed of sound in materials lead to very small time step in an explicit transient analysis. The simulation process is often not robust enough when the model experiences the large deformation. To shorten modeling and simulation times, we have developed a fast running model based on a novel nonlinear beam element for the skeletal impact biomechanics analysis. In contrast to the conventional beam elements, the kinematics of the developed beam element is free of rotational degrees of freedom (DOFs). The current beam element offers the desired constant lumped mass matrix for the large deformable explicit transient analysis. The realistic treatment of junctions and surface intersections among beams becomes straightforward. Furthermore the model can account for the irregular shape and different materials at beam cross sections by using the numerical integration. The sophisticated material models such as elastoplasticity can also be incorporated directly in the integration points. Thus the fast running model is suitable for the analysis of complex nonlinear composite structures such as the loading-carrying thoracic skeleton and extremities. The stereolithograph (STL)-based anatomical geometry of skeletal structure is used to extract the one-dimensional (1D) curved beam model and the associated beam cross sections. The anatomical surface of skeleton is also utilized for the calculation of transferred loads to the underlined beams. The 3D responses such as displacements and stresses from the fast running model are subsequently reconstructed on the anatomical surface for the visualization and skeletal trauma analysis. We demonstrate the efficiency of such modeling technique by simulating the rib cage and the lower extremity under the impact loadings. As compared to the 3D FEM model, the developed model runs fast and robust, and achieves good results without the need of laborious 3D meshing process.

The musculoskeletal system provides the body with both movement and support. In particular, contractile forces developed in the muscles are transmitted through the muscle-tendon junction (MTJ) into the tendon and then through the tendon-bone insertion into the bone. Each junction occurs between two dissimilar materials (muscle-to-tendon and tendon-to-bone) and neither is fully understood. The current study analyzes the relationship between the tissue microstructure and macro-scale biomechanical properties of the muscle-tendon-bone unit to better understand the anisotropic mechanical behavior of the tissue. Collagen content was assayed at various locations along the porcine digital flexor tendon. Collagen concentration as a percent of the wet weight in the bone end was found to be 20.4±5.2% (n=6), the mid tendon to be 20.6±5.3% (n=6), and the muscle end to be 25.2±3.6% (n=4). No statistical differences were found between these collagen concentrations. Additionally, to the best of the authors’ knowledge, this is the first study to report cross-sectional stress-strain data for the muscle-tendon-bone unit. Results indicate that the tendon cross-sectional stiffness increases from the proximal end to the distal end. However, no direction dependent anisotropies were found between the mediolateral and dorsopalmar directions. Effects of microstructural components, such as glycosaminoglycans and collagen, and phenomenon such as fibril sliding and cross-linking, are discussed in relation to the reported cross-section stress-strain response. This work provides a synergistic approach for quantifying biomechanical and biochemical properties of biological tissue, and potentially facilitates the development of tissue engineered MTJ and tendon-bone insertion.

Conceptual design is the first and most important phase of an aircraft’s configuration and system development process. That being said, there is no denying that innovation in aviation has stunted over the last 50 years; the once every present fascination of flying has been blanketed by the rapid profit-driven commercializing of an industry. Moreover, we have reached an apex of maximizing the efficiency of current passenger aircraft model configurations. In recent times, new research and development has culminated to the introduction of aerodynamic structures to address key issues such as stability and fuel efficiency. This research paper seeks to push the envelope of innovation with a brand new perspective on how we view air travel — redefining the Why, What and How. It explores novel concepts such as Boeing Blended Wing Body (BWB) aircraft shown in, which does not follow the conventional Tube and Wing (TAW) configuration. It is a tailless design that integrates the wing and the fuselage into a single-lifting surface. The most common advantages include a higher lift-to-drag ratio and higher payload capacity due to a distribute load along the centerline of the aircraft. On the other hand, a tailless configuration comes at a cost to in-flight maneuvering and stability. The unique design of the Hybrid-MCX-1 aircraft involves the application of the active aero-elastic tailoring to aircraft topology optimization for both subsonic and transonic regimes. With a focus on experimental wind tunnel testing and high-fidelity simulations, this project proposes a new concept that deviates from today’s tubular and wing concept. The aircraft has a unique shape with a forward fuselage that starts off with the conventional tubular and winged aircraft design currently flown in commercial travel, but deviates to a wider cross section at the center of the fuselage. The model has self-supporting, cantilever, dihedral, swept wings, with pronounced fillets at the junction of the wing root and fuselage, blending them smoothly. This smooth transition reduce interference between airflow over the wing root and the adjacent body surface, ultimately reducing drag. The engines of the Hybrid-MCX-1 are mounted by at 45-degree angle on the rear of the plane. This engine location offers the opportunity for swallowing the boundary layer of air from that portion of the center body upstream of the inlet, providing improved propulsive efficiency by reducing the ram drag. The Hybrid-MCX-1 also possesses a vertical tail that bisects the engines. As with current commercial aircraft, this tail provides lateral stability and controls the yaw. In the case of the BWB, yaw control is made possible by sweeping the wing and downloading the wingtips. However, this approach reduces the effective aerodynamic wingspan of the aircraft and imposes a significant induced drag penalty. The presence of a tail on the concept model addresses the aforementioned issue and rectifies unwanted yawing that may arise during cross wind flight conditions. The rear end of the aircraft decrease significantly in vertical thickness when compared to the lateral thickness to minimize the possibility of flow separation as air passes around the wings and over the front half of the aircraft while maximizing total lifting surface area. The pylons are adequately sized to avoid aerodynamic interference between fuselage, pylon and nacelle but still relatively short to minimize drag.

Thermal striping generally is recognized as a significant long-term degradation mechanism in the primary cooling water circuit of nuclear power plants (NPPs). This phenomenon occurs by mixing of hot and cold water streams in the primary coolant loop. Depending on the flow configuration, the turbulent mixing process can lead to thermal striping, temperature fluctuations in the T-junction region, thermal fatigue, and crack generation in the associated structure. The objective of this study is to provide an in-depth look into the underlying physics for thermal fatigue to determine appropriate screening criteria and risk significance for the regulatory safety evaluation process. In addition, the structure of turbulence in the T-junction also is investigated. The computational method comprised of Large Eddy Simulation (LES) modeling to simulate turbulence and Proper Orthogonal Decomposition (POD) analysis to capture the coherent structures and turbulence scales. In addition, Conjugate Heat Transfer (CHT) analyses have been performed to predict the thermal field and temperature distribution in the solid piping material of the T-junction. Finally, the corresponding thermal stress in the solid pipe is estimated based on a simplified one-dimensional model to assess the thermal-structure degradation.