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non-destructive testing, corrosion detection, guided wave, torsional wave, Mechanical engineering and machinery, TJ1-1570, Mechanics of engineering. Applied mechanics, and TA349-359

Ultrasonic guided wave testing is used in rapid screening to detect, locate and classify corrosion defects. This non-destructive testing technique can perform wide-range inspection from a single point, thus reducing the time and effort required for NDT. However, the mode conversion phenomena and the dispersive nature of the guided waves make corrosion detection difficult. Hence, the parametric studies on the response signals of a T (0, 1) wave from pipe defects were presented in this paper. Firstly, a mathematical model of 6-inch schedule 40 pipes was developed. The corrosion profile of various geometries was then constructed on the outer surface of the pipeline by varying the circumferential length and depth. The numerical study was performed to analyse the characteristics of the response signals when a torsional guided wave impinges on thecorroded pipelines. A five-cycle Hanning tone-burst signal with a central frequency of 30k Hz was used throughout the study. The results demonstrated that mode conversion to a flexural mode F (1, m) occurs when the stimulated T (0, 1) strikes non-symmetric defects. Nonetheless, as the circumferential extent of the corrosion increased, the response signals tended to behave symmetrically, and there was less mode conversion detected. Thus, the presence of flexural mode F (1, m) can be used as the criteria to distinguish symmetric and asymmetric faults. In addition, the results demonstrated that the reflection coefficients increase monotonically with the defect's depth due to the increases in the estimated cross-sectional area loss. As a result, a more significant proportion of the transmission wave was reflected. These findings serve as guidelines for on-site inspections. With the known speed of guided wave propagation, it is possible to precisely forecast the position of faults.

Intelligent transportation systems, Joint detection and tracking, Global correlation network, End-to-end tracking, Ocean engineering, TC1501-1800, Mechanical engineering and machinery, and TJ1-1570

Abstract Environment perception is one of the most critical technology of intelligent transportation systems (ITS). Motion interaction between multiple vehicles in ITS makes it important to perform multi-object tracking (MOT). However, most existing MOT algorithms follow the tracking-by-detection framework, which separates detection and tracking into two independent segments and limit the global efficiency. Recently, a few algorithms have combined feature extraction into one network; however, the tracking portion continues to rely on data association, and requires complex post-processing for life cycle management. Those methods do not combine detection and tracking efficiently. This paper presents a novel network to realize joint multi-object detection and tracking in an end-to-end manner for ITS, named as global correlation network (GCNet). Unlike most object detection methods, GCNet introduces a global correlation layer for regression of absolute size and coordinates of bounding boxes, instead of offsetting predictions. The pipeline of detection and tracking in GCNet is conceptually simple, and does not require complicated tracking strategies such as non-maximum suppression and data association. GCNet was evaluated on a multi-vehicle tracking dataset, UA-DETRAC, demonstrating promising performance compared to state-of-the-art detectors and trackers.

Electric field, Magnetic field, Microstructures, Mechanical properties, Solid metals, Ocean engineering, TC1501-1800, Mechanical engineering and machinery, and TJ1-1570

Abstract An external electric or magnetic field can transfer high-intensity energy directly to the electronic scale of materials, and change the spin, energy level arrangement and trajectory of electrons. These changes produce tremendous and profound impacts on the microstructure and mechanical properties of metal materials, which may be impossible with traditional technologies. This paper reviews the effects of electric or magnetic field on the microstructures of solid metals including phase transformation, precipitation, recrystallization, dislocations and so on. Based on the existing research results, the mechanisms of these effects have been discussed. Additionally, some typical applications of electric and magnetic treatments on solid metals have been described and the challenges in this field have also been discussed.

WORMESH-II, Multiple pedal waves, Sidewinding locomotion, Bio-inspired robot, Flatworm, Technology, Mechanical engineering and machinery, TJ1-1570, Control engineering systems. Automatic machinery (General), TJ212-225, Machine design and drawing, TJ227-240, Technology (General), T1-995, Industrial engineering. Management engineering, T55.4-60.8, Automation, T59.5, Information technology, and T58.5-58.64

Abstract WORMESH-II, which is the second prototype in the WORMESH series, is inspired by a flatten and soft-bodied fatworm, and its uniqueness is the use of multiple travelling waves for locomotion. In this paper, the sidewinding locomotions for WORMESH-II are talked about. This is because sidewinding is one of the most effective ways to traverse sandy terrain. The mathematical model of the sidewinding locomotion kinematics of WORMESH-II explains how synchronous multiple sidewinding waves can be used to control the movement of the robot effectively. Unlike WORMESH’s pedal-wave locomotion, sidewinding gaits allow the robot to be manoeuvred in any direction without changing the joint sequence. Relative to the wave propagation direction, velocity in the longitudinal direction is dependent on the vertical component of sidewinding travelling waves. Moreover, velocity in the transverse direction depends on the horizontal component of sidewinding travelling waves. The velocity in the longitudinal direction becomes zero when the phase shift of the travelling waves equals $$\pi $$ π rad. The angular velocity around the instantaneous centre of rotation depends on the wave amplitude of the horizontal component of the sidewinding travelling wave along the kinematic chains, and the turning radius is proportional to the amplitude gradient along the kinematic chains. The dynamic simulation of WORMESH-II and testing with the WORMESH-II prototype confirmed the proposed method, which was based on the metamathematical explanation of locomotion.

Multibody dynamics, 3D revolute joint, Wear prediction, Digital image correlation, Ocean engineering, TC1501-1800, Mechanical engineering and machinery, and TJ1-1570

Abstract The existence of the relative radial and axial movements of a revolute joint’s journal and bearing is widely known. The three-dimensional (3D) revolute joint model considers relative radial and axial clearances; therefore, the freedoms of motion and contact scenarios are more realistic than those of the two-dimensional model. This paper proposes a wear model that integrates the modeling of a 3D revolute clearance joint and the contact force and wear depth calculations. Time-varying contact stiffness is first considered in the contact force model. Also, a cycle-update wear depth calculation strategy is presented. A digital image correlation (DIC) non-contact measurement and a cylindricity test are conducted. The measurement results are compared with the numerical simulation, and the proposed model’s correctness and the wear depth calculation strategy are verified. The results show that the wear amount distribution on the bearing’s inner surface is uneven in the axial and radial directions due to the journal’s stochastic oscillations. The maximum wear depth locates where at the bearing’s edges the motion direction of the follower shifts. These findings help to seek the revolute joints’ wear-prone parts and enhance their durability and reliability through improved design.

Digital twin, Digital twin shop-floor, Synchronization in digital twin shop-floor, Synchronization mechanism, Satellite assembly shop-floor, Ocean engineering, TC1501-1800, Mechanical engineering and machinery, and TJ1-1570

Abstract In recent years, as a promising way to realize digital transformation, digital twin shop-floor (DTS) plays an important role in smart manufacturing. The core feature of DTS is the synchronization. How to implement and maintain the synchronization is critical for DTS. However, there is still a lack of a common definition for synchronization in DTS. Besides, a systematic synchronization mechanism for DTS is strongly needed. This paper first summarizes the definition and requirements of synchronization in DTS, to clarify the understanding of synchronization in DTS. Then, a 5M synchronization mechanism for DTS is proposed, where 5M refers to multi-system data, multi-fidelity model, multi-resource state, multi-level state, and multi-stage operation. As a bottom-up synchronization mechanism, 5M synchronization mechanism for DTS has the potential to support DTS to achieve and maintain physical-virtual state synchronization, and to realize operation synchronization of DTS. The implementation methods of 5M synchronization mechanism for DTS are also introduced. Finally, the proposed synchronization mechanism is validated in a digital twin satellite assembly shop-floor, which proves the effectiveness and feasibility of the mechanism.

Curved surface, Five-axis machining, Dimension reduction and mapping, Milling force, Dynamics, Ocean engineering, TC1501-1800, Mechanical engineering and machinery, and TJ1-1570

Abstract The equipment used in various fields contains an increasing number of parts with curved surfaces of increasing size. Five-axis computer numerical control (CNC) milling is the main parts machining method, while dynamics analysis has always been a research hotspot. The cutting conditions determined by the cutter axis, tool path, and workpiece geometry are complex and changeable, which has made dynamics research a major challenge. For this reason, this paper introduces the innovative idea of applying dimension reduction and mapping to the five-axis machining of curved surfaces, and proposes an efficient dynamics analysis model. To simplify the research object, the cutter position points along the tool path were discretized into inclined plane five-axis machining. The cutter dip angle and feed deflection angle were used to define the spatial position relationship in five-axis machining. These were then taken as the new base variables to construct an abstract two-dimensional space and establish the mapping relationship between the cutter position point and space point sets to further simplify the dimensions of the research object. Based on the in-cut cutting edge solved by the space limitation method, the dynamics of the inclined plane five-axis machining unit were studied, and the results were uniformly stored in the abstract space to produce a database. Finally, the prediction of the milling force and vibration state along the tool path became a data extraction process that significantly improved efficiency. Two experiments were also conducted which proved the accuracy and efficiency of the proposed dynamics analysis model. This study has great potential for the online synchronization of intelligent machining of large surfaces.

hybrid algorithm, uncoated tool, ti6al4v alloy, particle swarm–gravitational search algorithms, end milling, Mechanical engineering and machinery, and TJ1-1570

Titanium alloys are broadly used in the medical and aerospace sectors. However, they are categorized within the hard-to-machine alloys ascribed to their higher chemical reactivity and lower thermal conductivity. This aim of this research was to study the impact of the dry-end-milling process with an uncoated tool on the produced surface roughness of Ti6Al4V alloy. This research aims to study the impact of the dry-end milling process with an uncoated tool on the produced surface roughness of Ti6Al4V alloy. Also, it seeks to develop a new hybrid neural model based on the training back propagation neural network (BPNN) with swarm optimization-gravitation search hybrid algorithms (PSO-GSA). Full-factorial design of the experiment with L27 orthogonal array was applied, and three end-milling parameters (cutting speed, feed rate, and axial depth of cut) with three levels were selected (50, 77.5, and 105 m/min; 0.1, 0.15, and 0.2 mm/tooth; and 1, 1.5, and 2 mm) and investigated to show their influence on the obtained surface roughness. The results revealed that the surface roughness is significantly affected by the feed rate followed by the axial depth. A 0.49 µm was produced as a minimum surface roughness at the optimized parameters of 105 m/min, 0.1 mm/tooth, and 1 mm. On the other hand, a neural network having a single hidden layer with 1–20 hidden neurons, 3 input neurons, and 1 output neuron was trained with both PSO and PSO–GSA algorithms. The hybrid BPNN–PSO–GSA model showed its superiority over the BPNN–PSO model in terms of the minimum mean square error (MSE) that was calculated during the testing stage. The best BPNN–PSO–GSA hybrid model was the 3–18–1 structure, which reached the best testing MSE of 3.8 × 10−11 against 2.42 × 10−5 of the 3–8–1 BPNN–PSO hybrid model.

propeller hydro-turbine, computational fluid dynamics, vortex rope, pressure fluctuation, air admission, entropy production theory, Mechanical engineering and machinery, and TJ1-1570

For the purpose of automatic generation control (AGC), a portion of the propeller hydro-turbine units in China is adjusted to operate within a restricted range of 75%-85% load using computer-controlled AGC strategies. In engineering applications, it has been observed that when a propeller hydro-turbine unit operates under off-design conditions, a large-scale vortex rope would occur in the draft tube, leading to significant pressure fluctuations. Injecting air into the draft tube to reduce the amplitude of pressure fluctuations is a common practice, but its effectiveness has not been proven on propeller hydro-turbine units. In this study, a CFD model of a propeller hydro-turbine was established, and 15 cases with different guide vane openings (GVO, between 31° and 45°) under unsteady conditions were calculated and studied. Two air admission measures were introduced to suppress the vortex rope oscillation in the draft tube and to mitigate pressure fluctuations. The reason for the additional energy loss due to air admission was then explained by the entropy production theory, and its value was quantified. This study points out that when injecting air, it is necessary to first consider whether the air will obstruct the flow in the draft tube. Finally, based on simulation and experimental data under various load conditions, pressure fluctuation analysis (based on fast Fourier transform, FFT) was conducted to assess the effectiveness of air admission measures. This study can provide an additional option for balancing unit efficiency and stability when scheduling units using an AGC strategy.

fish-friendly turbine rotor, spiral curve, linear angle variation, hydraulic performance, design, optimization, cfd, Mechanical engineering and machinery, and TJ1-1570

Most large hydropower facilities employing conventional hydraulic turbines, e.g., Francis, Kaplan, or Bulb turbines, etc., cause significant harm to fish, resulting in high mortality rates, during turbine operation. This results from strong injury-inducing mechanisms at the rotor, including shear stresses, pressure variations, and pressure drop through the rotor. The study outlines a methodology for designing a fish-friendly turbine that is suitable for high-power generation applications. This methodology for a hydraulic channel design within the turbine rotor was derived based on classical fundamental applications of a rotor design, supplemented by subsequent assessments that incorporate fish-friendly design parameters that have been documented in the existing literature. A spiral curve characterized by a linear angle variation between the rotor's inlet and outlet was employed to project the blade geometry. Here, the Göttingen hydrofoil series was used, while a second-order polynomial function guided the hub design. Both of these parametrizations sought to enhance the turbine's hydraulic efficiency. Minimum Absolute Pressure, Strain Rate, and Pressure Variation Rate intervals were established as assessment criteria for fish survival for certain species, as has also been previously explored in the literature. The findings were outlined in terms of hydrodynamic performance and flow behavior within the rotor. An improvement in hydraulic efficiency was observed, transitioning from a Preliminary Turbine geometry design to an Optimized Turbine Geometry design. The turbine rotor was optimized using Computational Fluid Dynamics (CFD) simulations, generated from a Design of Experiments (DOE). Modifications to the hydrofoil type, the sweep angle, and the trailing edge angle of the blades were all made, coupled with integrations of assessments considering fish-friendly parameters.

pump as turbine, two-stage, energy dissipation, entropy generation theory, pumping and storage, Mechanical engineering and machinery, and TJ1-1570

Utilizing a two-stage vertical pump as turbine (TVPAT) is an economically method for constructing small-scale pumping and storage hydropower stations at high head-low discharge sites, such as underground coal mines. The energy dissipation mechanisms in flow passages are theoretically important for performance prediction and geometric parameter optimization. In this paper, the energy dissipation within the TVPAT has been studied using entropy generation theory, which can be applied to visual, locate and quantify energy dissipation. The numerical solution of entropy dissipation components was extracted on turbine modes in different flow rates using the steady-state single-phase SST k-ω turbulence model. The numerical results show that the energy dissipation in TVPAT mainly comes from turbulent fluctuation (43.6%-72.1%) and blade surface friction (27.8%-58.2%). The runners are the main source of turbulent entropy (SD′ ) generation (47.2%-83.3%). The contribution of the return channel and spiral case to the generation under overload conditions is significant, accounting for 33.6% and 14.3 at 1.3QBEP, respectively. Flow field analysis reveals that high generation within a runner are located in the striking flow region of the leading edge, the flow squeezing region in the blade channel, and the wake region of tailing edge. The mismatch between the placement angle of the blades or guide vanes and the liquid flow angle is an important incentive for SD′ generation. Moreover, hydraulic energy is consumed through the interaction between mainstream and local inferior flows such as separation and vortices, as well as the striking and friction between local fluid and wall surfaces.

cfd, film thickness, taylor flow, t-junction, two-phase flow, Mechanical engineering and machinery, and TJ1-1570

The laminar nature of flow in mini and microchannels has pushed researchers to develop novel solutions to overcome reaction rate reduction and heat/mass transfer issues. In this regard, Taylor flow is one of the possible solutions that could be used to enhance mixing inside mini and microchannels with reasonable pressure drop. The hydrodynamics of Taylor liquid-liquid flow is numerically studied in this work by employing two different droplet generation methods, specifically T-junction and patching methods. To this end, a three-dimensional model of rectangular microchannel flow is considered. The computational domain was designed and meshed by ICEM CFD and then simulated with commercial software ANSYS Fluent. The interface between the two phases was captured using the Volume of Fluid (VOF) method. The generating and development process of water droplets dispersed in an ethylene/propylene glycol carrier phase for both methods is discussed in detail. According to the results, both methods show satisfactory performance regarding liquid film and droplet shape, with only a slight difference. However, the patching method was found to be more economical in terms of computational time. This study would improve the state of knowledge on two-phase flow simulation in microchannels and thus contribute to the understanding of Taylor flow hydrodynamics.

inverted bow, resistance, sinkage, trim, computational fluid dynamics, Mechanical engineering and machinery, and TJ1-1570

This study discusses the inverted bow design on the combatant hull form. Changes in the shape of the stem angle and flare bow are used as analytical parameters to investigate the ship's performance. Ship resistance and motion will be predicted using the Computational Fluid Dynamics (CFD) approach using the Reynolds Averaged Navier Stokes (RANS) equation and the k-ε turbulence model. The volume of fluid (VOF) method is applied to simulate the change in the free surface between water and air using an overset mesh technique. The ship's movement is limited to sinkage and trim motions, so the movement's accuracy can be predicted. The results revealed that the inverted bow reduced the total resistance by 6.30%, whereas the trim and sinkage showed no significant changes. The breakdown of the reduction ratio showed that friction resistance components were reduced by 10.62%, wave resistance by 44.05%, and viscous-pressure resistance by 45.33%. This highlights the effectiveness of an inverted bow in optimizing wave and viscous pressure, enhancing overall ship performance.

wave energy, owc, cfd, sloshing, performance, Mechanical engineering and machinery, and TJ1-1570

Among various types of wave energy converters, the oscillating water column (OWC) has attracted significant research attention. In this paper, a 1:10 scale OWC with dimensions of 100×100×160 cm, variable inlet height and draft was numerically studied. Based on the tests conducted, it was found that the wave amplitude in the range of Caspian Sea waves decreased with the increase of wave frequency, to the extent that at the sloshing frequency, the system efficiency dropped significantly. To solve this problem, changes in the geometry of the device were studied, and numerical simulations were performed at the highest frequency using OpenFOAM software. Using Reynolds-averaged Navier-Stokes (RANS) equations, numerical simulations were performed in 3D, two-phase, and turbulent flow conditions. Changing the geometry was initially investigated by adjusting the height of the OWC inlet duct, and then by adding an inlet at the different angles of 0, 20, and 40 degrees. The results showed that by increasing the height of the inlet by 10 cm while keeping the water depth and wave conditions constant, the maximum output power of the system increased by 54%. However, after the optimization of the inlet duct, it was found that the best angle for an inlet duct is 30°, compared to the case without an inlet, which increased the maximum output power by up to 13% and slightly reduced the sloshing by more than 50%.

diversion groove, asymmetric nose, two-dimensional correction, ballistic correction projectile, cfd, Mechanical engineering and machinery, and TJ1-1570

A surface diversion groove with a specific geometry and position can influence the laminar flow characteristics of a projectile, which may affect the flight trajectory of an aircraft. The asymmetric flow field around the projectile can be induced by the diversion groove, which can produce an obvious aerodynamic force and moment at the projectile nose for trajectory correction. This study applied a diversion groove structure to the nose of tail-stabilized projectiles to investigate its impact on the aerodynamic characteristics of the projectile. The mathematical expressions for the aerodynamic force and aerodynamic coefficient were established theoretically. The change in the aerodynamic coefficient as a function of the phase angle of the diversion groove was determined. A parametric simulation was employed to investigate how the diversion groove affects the aerodynamic attributes of the projectile across various Mach numbers and angles of attack. The simulation results are consistent with the variation trends of aerodynamic forces and moments with respect to the phase angle of the diverter groove, as predicted by the static mathematical model. These findings demonstrate that the variation trends of the lift coefficient and pitching moment coefficient with respect to the angle β approximate a cosine function. Meanwhile, the variation trends of the yaw force coefficient and yaw moment coefficient with respect to the angle β approximate a sine function. The tail-stabilized projectile with asymmetrical diversion groove achieved a reduction of 1.2% in drag coefficient compared with that of the canard rudder corrective projectile, while the lift coefficient and pitch moment coefficient were increased by 6.4% and 16%, respectively, in the subsonic regime. The static margin of the projectile ranging from 13% to 16%. This study offers valuable insights for the design of corrective structures with diversion grooves and trajectory control.

numerical simulation, flow induced vibration, fluid-structure interaction, ejector system, cavitation, Mechanical engineering and machinery, and TJ1-1570

As one of the essential components of the conventional island in a nuclear power plant, the ejector supplies cooling water to the reactor core in an accident state. It needs serious maintenance for its structural stability. The flow-induced vibration of an ejector in service was numerically examined in this research while taking the cavitation phenomenon into account. To achieve this goal, a bidirectional fluid–structure interaction simulation based on the ANSYS platform was run. In our lab, an experimental loop was also set up to validate the fluid model. Then, under specific circumstances, it was possible to monitor the cavitation revolution process, pressure variation, and ejector vibration. According to the numerical results, the distribution of the vapor phase is largely found in the mixing and diverging portions, and it changes over time. In the ejector, a significant wideband excitation was observed. Additionally, the von Mises stress and flow-induced vibrational features of the ejector structure were investigated.

plunger valve, actuator, dynamic model, combination analysis, flow characteristics, Mechanical engineering and machinery, and TJ1-1570

The plunger valve has an important role in a large compressor system as its operating characteristics directly affect the aerodynamic boundary condition of the compressor equipment. In this study, dynamic modeling and analysis method of the plunger valve are proposed for an accurate control of the system. By considering the interaction between the dynamic flow in the valve and actuator action, a lumped parameter model for the fluid–structure interaction force and multibody dynamic model of the actuator are developed based on intrinsic correlation parameters. A combination analysis to simultaneously predict valve flow and actuator dynamic characteristics is proposed. The predicted results are in a good agreement with experimental data, which validates the proposed model and analysis method. The analysis results show that the coupling effect between the valve flow and actuator is significant and has an important role in valve control, particularly when the valve opening is smaller. Compared to the experimental data and computational fluid dynamics results, the presented methods are accurate for valve control and effective for prediction of flow rate.

hydropower, hydro-abrasive erosion, pelton injector, bend angle, nozzle and needle angle, Mechanical engineering and machinery, and TJ1-1570

In high-head Pelton turbines, the injector faces severe erosion due to suspended sediment leading to a reduction in turbine efficiency and higher maintenance costs. Here, the effects of design parameters such as the bend angle of the nozzle pipe, nozzle angle, and needle angle along with an operating parameter stroke ratio on hydro-abrasive erosion of Pelton turbine injector are numerically investigated. The Volume of Fluid (VOF) model was implemented for capturing the interphase between air and water; whereas, the SST k-ω model is used for modelling the turbulence effect. For tracking the discrete phase, a Eulerian-Lagrangian based Discrete Phase Model (DPM) is considered. The bend angles led to flow circulations in the nozzle pipe causing the non-uniform distribution of sediment concentration and uneven erosion patterns. Irrespective of the bend angle, the erosion hotspot in the needle is observed toward the bend side. Further, for larger sediment particles, higher bend angles lead to more erosion rate in both the nozzle and needle and must be avoided to prevent excessive damage. As the needle angle increases from 40° to 60° for a constant nozzle angle, the nozzle erosion rate increases by 70% and the needle erosion rate decreases by 99%. Hence, an injector design can be optimized in hydro-abrasive erosion conditions by selecting a needle angle between 40° and 60°. Further, the operation of the injector at too high and low a stroke ratio results in excessive erosion of the nozzle and needle, respectively. In this study, a stroke ratio of 0.45 is found to be the most suitable for hydro-abrasive erosion conditions. Moreover, the asymmetricity in the erosion pattern of the needle increases with needle angle and stroke ratio resulting in jet quality degradation, one major reason for efficiency reduction in Pelton turbines.

flow field prediction, turbulent flow, machine learning, data-driven, surrogate models, computational fluid dynamics, Mechanical engineering and machinery, and TJ1-1570

A novel approach is presented for predicting compressible turbulent flow fields using a neural network-based data-driven method. Accurate prediction in turbulent regions heavily relies on the resolution of available data. Traditional methods, employing image-based techniques by mapping scattered computational fluid dynamics (CFD) data onto Cartesian grids, encounter data scarcity in critical areas such as the boundary layer and wake. Recently, convolutional neural networks (CNN) have gained prominence as the most widely referenced technique in fluid dynamics, utilizing flow field images as datasets for flow field prediction. However, CNN requires datasets with a high pixel density to enhance training accuracy in crucial regions, thereby increasing the input data volume and machine training time. To address this challenge, our proposed method deviates from using flow field images and instead generates datasets directly from the flow field properties of CFD grid points. By employing this approach, several advantages are realized. Firstly, the network benefits from the favorable characteristics of unstructured grids, such as varying point spacing near the object surface and in the far field, which effectively reduces the amount of input data and consequently the machine training cost. Secondly, the construction of the training dataset eliminates the need for interpolation or extrapolation, thereby preserving the accuracy of CFD data. In this case, a simple multilayer perceptron can be trained using the proposed dataset. Various flow field properties, including static pressure, turbulent kinetic energy, and velocity components, can be predicted with high accuracy within a few seconds.

boltzmann equation, dsmc method, trmc method, mtrmc method, taylor series expansion, nano-plate, Mechanical engineering and machinery, and TJ1-1570

The study proposes a new method called MTRMC to simulate flow in rarefied regimes, which are important in various industrial and engineering applications. This new method utilizes a modified collision function with smaller number of inter-molecular collisions, making it more computationally efficient than the widely used direct simulation Monte Carlo (DSMC) method. The MTRMC method is used to analyze the flow over a flat nano-plate at various free stream velocities, ranging from low to supersonic speeds. The results are compared with those from DSMC and time relaxed Monte Carlo (TRMC) schemes, and the findings show that the MTRMC method is in good agreement with the standard schemes, with a significant reduction in computational expense, up to 51% in some cases.