Complex Flow Structures Research Articles

Analysis of microplastic behaviors in river-type lakes using a quasi-three-dimensional microplastic transport model.

Paldang Lake in South Korea is a river-type lake characterized by weak temperature stratification and a short water residence time. It exhibits complex flow structures resulting from the convergence of two major rivers, the North Han River (NHR) and the South Han River (SHR), and one small river, the Gyeongan Stream. Analyzing the spatio-temporal variations in microplastic (MP) concentration in Paldang Lake is important because of its significance as a water supply source for the metropolitan area. In this study, a quasi-three-dimensional MP transport model (MPT-Q3D) based on the Lagrangian particle-tracking technique was developed to analyze the trajectory and concentration distribution of MPs driven by shear dispersion in river-type lakes. Using the simulation results of MPT-Q3D, which were validated with MP monitoring data and EFDC simulations, we investigated the spatio-temporal variations in MP concentration during both low-flow and flood-flow periods. Simulation results showed that horizontal transport by shear flow contributed more to MP transport than vertical transport, including settling movements based on MP density. Thus, the MP transport during the low-flow period was significantly influenced by the recirculating flow induced by hydropeaking of the NHR, as well as flow blockage caused by the strong inflow momentum from the SHR. During the flood-flow period, flood discharge from the three tributary rivers had an equal influence on MP transport and the variation in MP concentrations around the water intake facilities. Furthermore, the MP residence time was primarily affected by variations in the flow characteristics of the inflowing tributaries rather than the properties of the MP types. Analysis of the influx and efflux of MPs in Paldang Lake revealed that polypropylene was the predominant constituent, accounting for 53.9 % and 75.2 % of all residual MPs during the low-flow and flood-flow periods, respectively.

Effect of internal crossflow on impingement cooling flow and heat transfer characteristics

The flow and heat transfer characteristics of a single-row impingement jet, fed by internal crossflow, are numerically investigated. The results showed that the internal crossflow propels a rapid coolant outflow on the leeward side of the hole, subsequently elevating the local impingement Reynolds number. Concurrently, the internal crossflow augments the heat transfer rate on the impingement target surface, with surges reaching up to 60 % in the local Nu number and 11 % in the average Nu number at low external crossflow. Counter-intuitively, the heat transfer enhancement due to the increase in local Reynolds number diminishes as the strength of the external crossflow increases. This phenomenon is attributed to the emergence of an in-hole counter-rotating vortex pair, whose interaction with the external crossflow induces elongation of the jet in the pitchwise direction. However, these enhancements in heat transfer rate are counterbalanced come at the expense of a more complex flow structure and higher flow losses. The weight of the internal and external crossflow on impingement cooling performance is also investigated using the overall thermal efficiency which considers both heat transfer and flow resistance and it is found that the external crossflow is the main culprit for the decrease in overall thermal efficiency.

Combining Computational Fluid Dynamics and Experimental Data to Understand Fish Schooling Behavior.

Understanding the flow physics behind fish schooling poses significant challenges due to the difficulties in directly measuring hydrodynamic performance and the three-dimensional, chaotic, and complex flow structures generated by collective moving organisms. Numerous previous simulations and experiments have utilized computational, mechanical, or robotic models to represent live fish. And existing studies of live fish schools have contributed significantly to dissecting the complexities of fish schooling. But the scarcity of combined approaches that include both computational and experimental studies, ideally of the same fish schools, has limited our ability to understand the physical factors that are involved in fish collective behavior. This underscores the necessity of developing new approaches to working directly with live fish schools. An integrated method that combines experiments on live fish schools with computational fluid dynamics (CFD) simulations represents an innovative method of studying the hydrodynamics of fish schooling. CFD techniques can deliver accurate performance measurements and high-fidelity flow characteristics for comprehensive analysis. Concurrently, experimental approaches can capture the precise locomotor kinematics of fish and offer additional flow information through particle image velocimetry (PIV) measurements, potentially enhancing the accuracy and efficiency of CFD studies via advanced data assimilation techniques. The flow patterns observed in PIV experiments with fish schools and the complex hydrodynamic interactions revealed by integrated analyses highlight the complexity of fish schooling, prompting a reevaluation of the classic Weihs model of school dynamics. The synergy between CFD models and experimental data grants us comprehensive insights into the flow dynamics of fish schools, facilitating the evaluation of their functional significance and enabling comparative studies of schooling behavior. In addition, we consider the challenges in developing integrated analytical methods and suggest promising directions for future research.

Experimental Research on Pressure Pulsation and Flow Structures of the Low Specific Speed Centrifugal Pump

The low specific speed centrifugal pump plays a crucial role in industrial applications, and ensuring its efficient and stable operation is extremely important for the safety of the whole system. The pump must operate with an extremely high head, an extremely low flow rate, and a very fast speed. The internal flow structure is complex and there is a strong interaction between dynamic and static components; consequently, the hydraulic excitation force produced becomes a significant factor that triggers abnormal vibrations in the pump. Therefore, this study focuses on a low specific speed centrifugal pump and uses a single-stage model pump to conduct PIV and pressure pulsation tests. The findings reveal that the PIV tests successfully captured the typical jet-wake structure at the outlet of the impeller, as well as the flow separation structure at the leading edge of the guide vanes and the suction surface. On the left side of the discharge pipe, large-scale flow separation and reverse flow happen as a result of the flow-through effect, producing a strong vortex zone. The flow field on the left side of the pressure chamber is relatively uniform, and the low-speed region on the suction surface of the guide vanes is reduced due to the reverse flow. The results of the pressure pulsation test showed that the energy of pressure pulsation in the flow passage of the guide vane occurs at the fBPF and its harmonics, and the interaction between the rotor and stator is significant. Under the same operating condition, the RMS value distribution and amplitude at fBPF of each measurement point are asymmetric in the circumferential direction. The amplitude of fBPF near the discharge pipe is lower, while the RMS value is higher. A complex flow structure is shown by the larger amplitude and RMS value of the fBPF on the left side of the pressure chamber. With the flow rate increasing, the energy at fBPF of each measurement point increases first and then decreases, while the RMS value decreases, indicating a more uniform flow field inside the pump.

Complex flow field analysis in Multi-Shaft stirred Reactors: Dynamics of Wave-Vortex coupling revealed by POD and DMD methods

Insufficient understanding of complex flow structures in multi-shaft stirred reactors hinders industrial adoption. In this work, Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) methods were used to analyze the Large-Eddy Simulation (LES) results of the stationary and rotating zones for three types of stirred reactors, including multi-shaft configurations. The results indicate that the flexible spatial distribution of the impellers in multi-shaft stirred reactors enhances fluid interactions, leading to the superior performance in energy cascading, flow field self-regulation, and wave-vortex coupling. Frequency analysis of single modes underscores DMD’s efficacy in interpreting complex flow phenomena. Based on this, the DMD modal coefficients were fitted to equations, clarifying the development process of wave-vortex coupling within the stirred reactors. Additionally, by integrating fundamental fluid mechanics equations with the outcomes of the DMD method, a wave-vortex coupling model was developed, which is anticipated to yield a more accurate representation of the flow field.

A Hybrid RANS/LES Model for Predicting the Aerodynamics of Small City Vehicles

Electric city vehicles are vital for reducing pollution in urban areas due to their zero emissions and high energy efficiency, significantly improving air quality and reducing the carbon footprint. This study investigates the aerodynamic behavior of simplified city vehicle models using computational fluid dynamics (CFD) simulations based on Reynolds-Averaged Navier-Stokes (RANS) and Detached Eddy Simulation (DES) turbulence model. The models are tested at speeds of 10 m/s, 15 m/s, and 20 m/s, with a grid independence study to ensure reliable results. ANSYS Fluent is used for the simulations, comparing the results from RANS and hybrid RANS/LES or DDES in terms of aerodynamic forces and flow patterns around the vehicle. Results show that the drag coefficient (Cd) decreases with increasing speed for both RANS and DDES models. At 10 m/s, the drag coefficients are 0.541 for RANS and 0.524 for DDES, a 3.14% reduction. At 15 m/s, the drag coefficients are 0.539 for RANS and 0.518 for DDES, a 3.89% reduction. At 20 m/s, the drag coefficients are 0.538 for RANS and 0.514 for DDES, a 4.46% reduction. Flow visualizations show that DDES simulations capture more detailed and complex flow structures, particularly in the wake region, compared to the smoother RANS patterns. These findings are essential guidelines for optimizing vehicle design to enhance aerodynamic performance and contribute to the development of more efficient, environmentally friendly urban transportation solutions.

Numerical modelling of aerodynamic response to gusts and gust effect mitigation

Unmanned aerial vehicle (UAV) flights in urban environments are challenging due to the complex flow structures and elevated turbulence around buildings. Consequently, research has shifted towards investigating the impact of gusts on the aerodynamic stability and control of UAVs. This study focuses on enhancing gust numerical modelling capabilities to understand the aerodynamic response, specifically exploring gust mitigation strategies for UAVs operating in turbulent urban environments. The split-velocity method, originally designed for two-dimensional compressible inviscid flows, where the velocity components were decomposed into a prescribed gust velocity and the remaining velocity components, is extended to three-dimensional incompressible viscous flows. To facilitate effective gust mitigation techniques, a radial basis function is applied to the modified split-velocity method to numerically model wings in pitching motions under gust encounters. A novel strategy is proposed to correct the discretized gust velocities and ensure gust flux conservation, showing effective improvement to the numerical predictions. The computed results agreed well with the experimental data available in the public domain, confirming that wing pitch motion can effectively mitigate the effects of gusts.

Influences of channel bed morphology on flow structures in continuous curved channels

Introduction: The formation of bars and pools, characterized by concave and convex bed morphology, is a typical feature of curved rivers. The channel bed morphology has a significant influence on the flow structures in curved channels.Methods: Based on data from physical model experiments, this study employs the RNG k-ε model and the VOF (Volume of Fluid) method to perform three-dimensional numerical simulations of flow in continuous curved channels.Results: By comparing the variations in flow structures between channels with a flat bed and channels with bars and pools, the results show that the presence of bars and pools leads to an increase in longitudinal flow velocity on the convex bank side near the entrance of the upstream bend, while in the downstream bend it is opposite. The high-velocity region shifts slower towards the concave bank along the bend. The presence of point bars weakens the circulation near the convex bank in the upstream bend, resulting in a smaller circulation intensity. The decrease in circulation intensity is the largest (−23.91%) at the apex of the bend. In the downstream bend, the remaining circulation from the upstream bend attenuates slower in the pool and has a greater impact distance, increasing the circulation intensity in the downstream bend. The section near the bend entrance shows the largest increase in circulation intensity, with a rate of 128.18%. The unevenness of the bed topography increases the unevenness of the bed shear stress in the downstream bend.Discussion: The findings of this study contribute to a deeper understanding of the complex flow structures and evolution trends in natural curved rivers, providing scientific basis for the management of curved river channels.

Experiment investigation on secondary flow loss and flow control mechanisms in a variable compressor cascade with penny cavities

Variable Stator Vanes (VSVs) with penny cavities are an important method to improve the efficiency of compressors. However, the annular and radial gaps in VSVs introduce complex flow structures, posing challenges in enhancing compressor efficiency. This article employs low-speed wind tunnel experiments to study the impact mechanisms of VSVs' adjustment angle and radial gap size on secondary flow losses and implements single-hole suction as a means of flow control to reduce total pressure loss. The results indicate that radial gap leakage has a certain inhibitory effect on annular gap leakage at general adjustment angles. Total pressure loss decreases initially as the radial gap increases but once the radial gap further enlarges and dominates the loss components, the total pressure loss increases proportionally with the radial gap. At extreme adjustment angles, where the lateral pressure gradient is significant, radial gap leakage intensity is high and comprises the major part of the loss, leading to an increase in total pressure loss in proportion to radial gap enlargement. Additionally, single-hole suction is effective under various conditions, with the potential to reduce total pressure loss by up to 19.4 %. These findings provide guidance for the application of VSVs in further improving compressor efficiency.

Integrated Single Camera µPTV And Florescence Imaging For Cell Tracking And Flow Investigation In Centrifugal Microfluidic Devices

A micro-hydrocyclone is investigated as a high throughput particle/cell sorting microfluidic device. A complex flow structure has been reported by limited numerical works that increases the importance of undertaking a comprehensive experimental investigation. In addition to the flow, utilizing damageable bio cells in a micro-hydrocyclone, requires a deep understanding of the interaction between the cells entering the device, the flow structure and its instabilities forming in different operational phases. In such cases the implementation of multiple measurement techniques can be challenging due to the small scale of devices, here < 5 mm diameter. Therefore, for this complex flow an experimental approach is introduced to capture the flow structure and the motion of cells. In this method, tracer particles and fluorescent stained cells are captured simultaneous by a single camera in the same flow field. A custom image processing scheme is used for partitioning cells and particles from the raw data. To determine velocity vectors, µPTV is employed on the segmented data sets to study the effect of flow on trajectory and velocity of each individual cell in the system. By a combined investigation in a vast range of Reynolds number (50<Re<800) the dynamics of cells are investigated in response to different flow structures and flow regimes.

2D3C Measurement Of Velocity, Pressure And Temperature Fields In A Intake Flow Of An Air Turbine By Filtered Rayleigh Sattering (FRS) And Validation With LDV And PIV

A Filtered Rayleigh Scattering Technique is implemented in two different experimental setups and compared to the established velocity measurement techniques Laser Doppler Anemometry (LDA) and Particle Image Velocimetry (PIV). The Frequency Scanning Filtered Rayleigh Scattering Method employed uses an imagefiber bundle which allows for the simultaneous observation of the flow situation from six independent perspectives, utilizing only one sCMOS camera. A testrig with a nominal diameter of 80 mm was implemented by ILA R&D GmbH. Here measurements with straight pipe flow and a swirl generator were realised, as well as comparisions with LDA. A second experiment utilized Cranfields University’s Complex Intake Facility (CCITF), enabling the simulation of the flow field for an engine intake as observed behind an S-Duct diffuser. The diameter in the measuring plane was 160 mm. Measurements up to a mach number of 0.4 were performed and compared with HighSpeed Stereo-PIV (S-PIV) measurements. Good agreement was achieved in respect to both the absolute magnitude of the velocity measurements as well as to the resolution of complex flow structures. The developed FRS multi-view Setup is able to simultaneously determine the 3D velocity components, the pressure and the temperature on a measurement plane with high resolution and without seeding. After calibration the FRS system yields the pressure and temperature within 3 percent respectively 0.8 percent of the reference values. The measured velocity was within 1-2 m/s of the reference.

3D Lagrangian Particle Tracking In A Model Of The Human Airways

The three-dimensional flow field in the trachea of a physiologically correct model of the human respiratory tract from the nasal/oral cavities up to the 6th bronchi generation is investigated. The investigations comprise steady inflow conditions, i.e., steady inhalation and oscillatory flow combining inspiration and expiration to simulate calm breathing. A realistic breathing pattern is approximated by a sinusoidal waveform for two Womersley numbers of 3 and 4.5 and two Reynolds numbers of 400 and 1200. Due to the inherent three-dimensional and asymmetric nature of the flow field, 3D particle-tracking velocimetry (3D-PTV) measurements are performed using the Shake-The-Box (StB) algorithm to determine the influence of oral and nasal inhalation and exhalation on the flow field in the lower human airways. By using a refractive-index matched fluid consisting of water and glycerin, the complex flow structures inside the trachea are fully resolved. During oscillatory inhalation/exhalation, an integration window size of 6/40 pi was chosen as it can be considered short enough to assume a steady state. The PTV measurements confirm that the nasal and/or oral cavity must be taken into account when analyzing the flow field in the lower respiratory tract. Characteristic sets of velocity profiles in the sagittal and coronal plane of the trachea as well as contour plots evidence nearly identical flow structures for both oral and nasal inhalation, but also reveal that the presence of both cavities possesses a huge impact on the flow field compared to ideal, i.e., fully developed inflow conditions

Simulation of Flow and Pressure Loss in the Example of the Elbow

One of the most basic issues in fluid mechanics is the description of flow in closed flows; more precisely, the calculation of pressure drops and the description of the flow form. Therefore, in this paper, the numerical simulation of the flow through the elbow was presented. This case was used to comprehensively describe the most important phenomena that should be taken into account during closed flows. The elbow was chosen as one of the most frequently used fittings in practice. The simulation was made with ANSYS Fluent, with the use of the turbulent model k-ω, SIMPLE simulation method, and at Reynolds number . The minor and major pressure loss were presented and discussed in the paper. The minor loss coefficient at the high Reynolds number was equal to around 0.2, which is close to the value of 0.22 used in engineering calculations. The influence of the Reynolds number on the shift of the stream separation point in the elbow was described. The secondary flow in the elbow was observed and the vortex structure was discussed and shown with the use of the Q-criterion (Q iso surface for level 0.005). This analysis allowed us to better visualize and describe the complex flow structure observed in the investigated case.

Low-mass planets falling into gaps with cyclonic vortices

ABSTRACT We investigate the planetary migration of low-mass planets ($M_p\in [1,15]\, \mathrm{ M}_{\oplus }$, here $\mathrm{ M}_{\oplus }$ is the Earth mass) in a gaseous disc containing a previously formed gap. We perform high-resolution 3D simulations with the fargo3d code. To create the gap in the surface density of the disc, we use a radial viscosity profile with a bump, which is maintained during the entire simulation time. We find that when the gap is sufficiently deep, the spiral waves excited by the planet trigger the Rossby wave instability, forming cyclonic (underdense) vortices at the edges of the gap. When the planet approaches the gap, it interacts with the vortices, which produce a complex flow structure around the planet. Remarkably, we find a widening of the horseshoe region of the planet produced by the vortex at the outer edge of the gap, which depending on the mass of the planet differs by at least a factor of two with respect to the standard horseshoe width. This inevitably leads to an increase in the co-rotation torque on the planet and produces an efficient trap to halt its inward migration. In some cases, the planet becomes locked in co-rotation with the outer vortex. Under this scenario, our results could explain why low-mass planets do not fall towards the central star within the lifetime of the protoplanetary disc. Lastly, the development of these vortices produces an asymmetric temporal evolution of the gap, which could explain the structures observed in some protoplanetary discs.

Study on the evolution stages of the flow field induced by an alternating current sliding discharge plasma actuator in different actuation modes

The present study investigates the discharge and flow characteristics of a sliding discharge (SD) driven by alternating current (AC) and negative direct current (DC) high voltage in continuous operation and burst-mode actuation in quiescent air. The burst frequency f is set at 20, 40, 50, and 100 Hz with a duty cycle τ fixed at 50%. Different actuation cases exhibit similar discharge morphologies and electrical properties. The results indicate that the flow induced by the horizontal body force generated by the SD undergoes the following stages: formation, intensification, accumulation, and stabilization. Based on the effects of the body force, the evolution of the induced flow field can be divided into three stages: the initial stage (starting-vortex stage), the transition stage, and the final stage. In continuous operation, the transition stage is marked by a complex flow structure, while the final stage is distinguished by a deflecting jet. When the burst frequency f ≤ 50 Hz, the duration of the transition stage increases with the burst frequency, and it becomes transient at f = 100 Hz due to the short voltage input time. Phase-averaged particle image velocimetry results indicate that the final stage of the burst-mode actuation can be categorized into three types mostly based on the interaction of the vortices from the AC and DC electrodes. Compared to the continuous operation, the application of the burst-mode actuation in this study has a shorter transition stage duration, resulting in a more rapid realization of flow control.

Numerical study on dynamic flow of flexible extension nozzle in rocket motors

The use of extension nozzles in rocket propulsion systems is one of the effective methods to increase the geometric expansion ratio and thrust of the nozzle. As a new type of extension nozzle, the flexible extension nozzle can achieve continuous changes in nozzle expansion ratio. To explore the characteristics of the flow field structure at the “bulge” structure and the step structure in the actual configuration of the flexible extension nozzle, and the impact on the performance of the nozzle, a three-dimensional numerical simulation model of the flexible extension nozzle was first established to study the flow field at the “bulge” structure, and then a two-dimensional unsteady numerical simulation model was established by using the coupling technology of dynamic grid and overlapping grid to study the flow field at the step structure. The results show that during the unfolding of the nozzle surface, a complex flow structure of “expansion fan-mixing layer-shock-vortex” were formed in the step area at the junction of the fixed section and the moving extension section. The specific impulse loss of the 3D model is larger than that of the 2D model due to the consideration of the “bulge” structure. The flow loss of the “bulge” structure and the step structure to the nozzle is 0.73% and 0.65% respectively.

Experimental and numerical convective heat transfer performance analysis of a confined impinging round jet with triangular tabs under crossflow influence

In this study convective heat transfer performance of a confined impinging round jet with/without nozzle tabs under channel crossflow is investigated experimentally and numerically for a wall mounted heated module. Numerical investigations are carried out for different jet to crossflow velocity ratios (Vr) and compared to experimental data. Four different Vr values (5,6,8, and 10) are tested for single target plate distance to jet nozzle diameter ratio (H/D=8). ANSYS Fluent software is used for numerical simulations while infrared thermography is utilized for experimental investigations. Surface temperature values of the wall mounted module are obtained and presented along with complex flow structures obtained via numerical simulations. Results show that crossflow has decisive effect on temperature distribution on the component. By inserting triangular tabs to the nozzle exit, it is possible to further decrease the surface temperature of the module and minimize the crossflow caused jet deflection. The addition of triangular tabs resulted in a significant increase of up to 10% in the mean Nusselt number on the top surface of the module at Vr=10.

Manifold regularized deep canonical variate analysis with interpretable attribute guidance for three-phase flow process monitoring

Oil–gas–water three-phase flow has multiple flow states, exhibiting dynamic, nonlinear, and instantaneous behaviors. Monitoring and analysis of flow state are crucial for ensuring safe operation of industrial processes. However, the absence of a universal definition for three-phase flow states, owing to the complex flow characteristics and structures, leads to that labeling three-phase flow states by categories is impractical. For comprehensive monitoring and analysis, the flow states should be described from both global (e.g., the dominant phase) and local (e.g., the interphase structure) aspects. Given the aforementioned challenges, the work aims to address the accurate identification of typical three-phase flow states and to meticulously monitor and analyze the continuous evolutionary process of three-phase flow. To achieve it, the manifold regularized deep canonical variate analysis with attribute guidance (Ag-MRDCVA) is proposed, which not only introduces an innovative monitoring paradigm that designs state attributes for process description but also facilitates knowledge transfer from typical flow states to transition states. For enhancing the model’s feature embedding capabilities, an attribute guidance module is introduced to increase supervision information at both class and attribute levels. Then, convolutional neural network (CNN) backbones are developed with a dual objective of global serial correlation and local manifold regularization, which capture spatiotemporal information at both global and local scales, facilitating effective attribute encoding and characterization of flow states. Finally, the attribute evolution heat map and a monitoring metric (MM) collectively offer a compelling and comprehensive analysis of the three-phase flow process. Extensive experiments demonstrate that Ag-MRDCVA surpasses existing methods, showcasing its ability to minutely monitor the process while providing reasonable explanations.

Analysis of the directional and spectral distributions of kinetic energy in aortic blood flow

It has been recognized that blood flow in large vessels, such as the aorta, may undergo a transition to turbulent flow in the presence of cardiovascular disorders, while flow in the healthy aorta is perceived to be laminar under normal physiological conditions. However, this perception has been challenged by several studies, highlighting the need to consider more fundamental flow characterizations. The present study aims to provide a comprehensive analysis of the directional and spectral distributions of kinetic energy in aortic flows under normal and pathological conditions. For this purpose, large-eddy simulation results for two patient-specific aortas, representing a healthy aorta and an aorta with aortic valve stenosis, respectively, were analyzed by decomposing the resolved transient velocity fields into directional and frequency components. It is shown that fundamental characteristics, such as the distinctive role of harmonics of the cardiac cycle as well as intermediate frequencies, indicate complex flow structures and turbulence over the entire thoracic aorta in both cases. The high-frequency components of kinetic energy are found to decrease by more than one order of magnitude from regions associated with complex flow features to the descending aorta. In conclusion, the capability of such analyses to effectively describe complex aortic blood flow at physiological and pathological conditions is demonstrated and motivates further efforts to achieve a more fundamental understanding of the true nature of aortic blood flow.

Nonequilibrium Flow Simulations Using Unified Gas-Kinetic Wave-Particle Method

Nonequilibrium flows are commonly encountered in aerospace engineering applications such as spacecraft reentry, rocket launch, and satellite attitude control. Numerical simulations help greatly in the understanding of nonequilibrium flow, multiscale effects, and the dynamics in these applications. Coupling particle transport and collision within the gas evolution process, the unified gas-kinetic wave-particle (UGKWP) method has been developed for multiscale flow simulation, offering a strategy that strikes a balance between accuracy and efficiency. In the present study, the UGKWP method simulates challenging flow problems with large Knudsen number variations, including supersonic flow around a sphere, hypersonic flow around a space vehicle, nozzle plume into vacuum, and side-jet impingement on the hypersonic flow. The UGKWP accurately captures complex flow structures and has been verified through experimental data or direct simulation Monte Carlo results. Regarding computational cost, the UGKWP method requires only 60 GiB of memory to simulate the three-dimensional space vehicle with 560,593 cells under various flow conditions, which is manageable even on personal workstations. Given its excellent efficiency and accuracy, the UGKWP method shows its substantial benefits in simulating multiscale flow for aerospace engineering applications.