Field Structure Research Articles

Challenges in Forecasting the Evolution of a Distorted CME Observed During the First Close Solar Orbiter Perihelion

Coronal Mass Ejections (CMEs), drivers of the most severe Space Weather disturbances, are often assumed to evolve self-similarly during their propagation. However, open magnetic field structures in the corona, leading to higher-speed streams in the ambient solar wind, can be source of strong distortions of the CME front. In this paper, we investigate a distorted and Earth-directed CME observed on 2022 March 25 combining three remote sensing with three in situ observatories at different heliocentric distances (from 0.5 to 1 au). Near quadrature observations by Solar Orbiter and the Solar Terrestrial Relations Observatory revealed a distortion of the CME front in both latitude and longitude, with Solar Orbiter observations showing an Earth-directed latitudinal distortion as low as ≈6 R ⊙. Near-Earth extreme-ultraviolet observations indicated the distortion was caused by interaction with faster wind from a nearby equatorial coronal hole. To evaluate the effect of the distortion on the CME's propagation, we adopted a three-point-of-view graduated cylindrical shell (GCS) fitting approach. For the first time, the GCS results are combined with an additional heliospheric single-viewpoint that looks further out in the heliosphere, revealing a deceleration in the CME before reaching ≈100 R ⊙. The CME geometry and velocity determined by this enhanced GCS are used to initialize a drag-based model and a WSA-Enlil MHD model. The estimated times of arrival are compared with in situ data at different heliocentric distances and, despite the complexity of the event, the error in the arrival times at each spacecraft results much lower (≈4 hr error) than the typical errors in literature (≈8–10 hr).

Influence of fluidic shock control on the combustion flow field of a dual-mode scramjet

To improve the resistance capability of a dual-mode scramjet isolator, fluidic shock control devices with different control parameters were designed. First, the effects of the control parameters on the position distribution, morphological structure, evolution process of the shock train in the isolator and the resistance capability of the isolator were numerically simulated. Then, cold- and hot-state tests of the scramjet through a direct-connected pulse combustion wind tunnel were carried out at a simulated flight Mach number of 4 to obtain the ignition and combustion process in the scramjet combustor under fluidic shock control through measurements by high-speed schlieren and pressure transducers. Finally, the influence of fluidic shock control on supersonic combustion was analysed by comparing the flow field structure and combustion process with and without a control device at different equivalent ratios and under different fuel injection schemes. The results showed that the fluidic shock control parameters with a great influence on the resistance capability of the isolator were the angle and width of the suction slot and the angle of the injection slot and that the resistance capability of the isolator could be effectively improved by reasonably designing the control parameters. Under fluidic shock control, the morphological structure and positional distribution of the shock train showed an obvious hysteresis evolution process near the injection slot and the suction slot in the isolator with increasing and decreasing back pressures, and this hysteresis effect could further improve the combustion performance of the combustor.

Effects of windbreak types on aerodynamics of high-speed trains traversing from flat ground to semi-cutting and semi-embankment under crosswinds

Under the operation of strong crosswinds, the aerodynamic performance of high-speed trains (HSTs) will be seriously deteriorated when the transition section of flat ground and semi-cutting and semi-embankment (FGSCSE) is traversed, and the setting of windbreaks will help to slow down the impact of strong crosswinds on the trains. In this study, a three-dimensional coupled computational fluid dynamics numerical model to assess the aerodynamic performance of train–windbreak–FGSCSE–air system is developed. A comparative assessment is carried out to identify the variations in aerodynamic performance on the train carriage: no windbreak (NW), 50% ventilation windbreak (VW), and solid windbreak (SW), and the reasons for these variations are elucidated by examining the flow field structure's evolution. Furthermore, the operational safety of the train is discussed based on the indicator of wheel unloading ratio (fΔQ). Across the three distinct conditions, significant abrupt changes in aerodynamic load coefficients (ALCs) and the shedding of vortex structures are experienced by HSTs traversing the FGSCSE transition sections. Compared to the VW condition, the NW and SW conditions result in a greater number of shedding vortices on the leeward side and the tail of the train, and the VW condition results in the smallest magnitude of ALCs fluctuation. The power spectral density peak values of the aerodynamic loads follow the order: SW > NW > VW. Upon the train fully enters the subsequent operational environment, the VW condition has the smallest standard deviation of these coefficients. The standard deviations of CFy, CFz, CMx, CMy, and CMz for the head train in the VW condition are only 57.17% (46.81%), 55.85% (54.15%), 72.74% (34.62%), 57.99% (51.92%), and 44.60% (43.82%) of the corresponding values in the NW (SW) condition, respectively. In the NW, VW, and SW conditions, the fΔQ exceeds 0.9 when the wind speeds reach 30, 40, and 35 m/s, respectively. The windbreak with a ventilation rate of 30% performs the best, providing the most effective safety and stability for train operation.

Bioinspired flow Fields: A numerical investigation into Nature-Mimicking designs for boosting vanadium redox flow batteries

Efficient flow field structures are crucial for improving the performance of all-vanadium redox flow batteries (VRFBs). Considering the large pressure drop and pump losses in traditional serpentine flow fields (SFF), this paper proposes a novel biomimetic flow field structure (BFF) for VRFB. A three-dimensional multiphysics model comparing SFF and BFF designs for VRFB is developed, the assessment was further enhanced by considering the impact of electrolyte flow rates on multiple performance indicators. The results show that BFF’s unique design substantially reduces pressure drop, especially at higher flow rates. For both SFF and BFF designs, at a low flow rate of 60 ml/min, the SFF has a slightly higher pump-based voltage efficiency, but as the flow rate increases to 120 ml/min and 180 ml/min, the BFF outperforms the SFF, demonstrating advantages of 2.057 % and 6.888 %, respectively. This comprehensive VRFB modeling analysis provides valuable insights into optimizing future flow battery designs.

SEMANTIC FIELD “POWER” IN’S NOVEL “THE ARC FOR THE UNINVITED” BY VLADIMIR MAKSIMOV

The article presents a comprehensive description of the semantic field ‟Power” in the novel by the well-known Russian prose writer of the 2nd half of the 20th century, Vladimir Yemelyanovich Maksimov. The purpose of the study is to identify the structural and semantic features of the field, the communicative and pragmatic properties of its nuclear components, which are semantic dominants of the text and actively participate in organising the artistic narrative, depicting characters and events, and explicating the conceptual content of the study. An analytical review of the main linguistic studies devoted to the study of the phenomenon of authority in Russian culture and linguistic consciousness, and the scientific description of semantic fields in the system of language and speech is carried out. Modelling the field structure of the novel is based on the principles of discourse analysis of the text, and it is determined by the specifics of the writer’s linguistic personality, the individual originality of the artistic picture of the world, the genre-stylistic and plot-compositional features of the work, and the linguacultural situation of the depicted era. The component composition of the field, its core, centre and periphery, and microfields are consistently characterised. Semantic connections and intersections of field components are determined with contextual conditionality of additional meanings revealed. The semantic field ‟authority” combines four microfields: the central part of the field structure includes the microfields ‟state authority” and ‟God power”, the peripheral zone includes the microfields ‟family authority” and ‟authority and power of natural elements”. The core of the field includes the key lexemes of authority, power and the leader. The semantic dominants of the text, being components of the analysed field structure, contribute to the development of action in space and time, create narrative polyphony, reflect the author’s position, and convey the bright features of the writer’s linguistic personality.

From Origins to Trends: A Bibliometric Examination of Ethical Food Consumption.

Ethical food consumption has gained significant attention in the past years, reflecting a societal shift towards ethical behavior. Our study examines the evolution of ethical food consumption research over the past three decades, aiming to map its transformation. We identified key trends, influential contributors, and major thematic clusters through a bibliometric analysis, employing VOSviewer (v.1.6.18) for bibliometric visualization, focusing on citation networks and keyword o-occurrences to reveal the field's structure and dynamics. We made extensive use of the Web of Science database, where we selected 1096 relevant articles and review papers. Our analysis shows a notable rise in publications starting in 2005, with a peak in 2022, indicating increased scholarly interest in the topic. The findings underscore the importance of integrating empathy and human values into ethical food consumption, highlighting the critical roles of animal welfare, sustainability, and social justice. Despite a strong pro-ethical attitude among consumers, a significant "attitude-behavior gap" persists, emphasizing the need for strategies that bridge this divide. Our results emphasize the importance of interdisciplinary efforts to align ethical practices with broader societal goals, offering valuable insights for future research and policy-making to promote sustainable and ethical food consumption worldwide.

Surrogate-based shape optimization and sensitivity analysis on the aerodynamic performance of HCW configuration

With an additional wing upon the fuselage, the novel high-pressure capturing wing (HCW) configuration exhibits remarkable aerodynamic characteristics at hypersonic speeds under beneficial aerodynamic interference. This bi-wing structure can also enhance the lift at subsonic speeds, positioning HCW configuration as an excellent aerodynamic layout under wide-speed range conditions. In this paper, a single-wing principle HCW configuration is carried out to analyze the influence of the variations in the geometric parameters of the HCW on the aerodynamic performance. Drawing on extant research, four key geometric parameters of the HCW are chosen as design variables, and the hypersonic as well as supersonic conditions are selected for surrogate-based shape optimization. Utilizing polynomial response surface method and method of moving asymptotes, the single-objective optimization studies are carried out with the objectives of maximum lift-to-drag ratio at Ma = 6 and minimum drag coefficient at Ma = 3. Subsequently, the sensitivity analysis is performed for each design parameter. The above methods exhibit notable precision and favorable results. The results show that except for the leading-edge sweep angle, the other three optimization results exhibit divergent trends in their variations. The setting angle has the most significant influence on the aerodynamic forces, owing to the influences of its variation on the shock wave intensity and reflection angle. Based on the stronger intensity of shock wave, this sensitivity indices are higher at Ma = 6. The other three parameters (half-span, leading-edge sweep angle, and trailing-edge sweep angle) modify the aerodynamic forces by adjusting the area of high-pressure region on HCW. Due to the different flow field structures, optimum parameters exhibit diverse effects on lift coefficient and lift-to-drag ratio.

LEXICAL AND SEMANTIC CORRESPONDENCE IN POLITICAL DISCOURSE ON INTERNATIONAL ARMED CONFLICTS

Discourse affects the semantics of lexical units. Discursively dependent semantics presents a challenge for intercultural communication. This study proposes a method for identifying the discursively dependent semantics of lexical units through an analysis of the discourse on the conflict in Syria, presented in the Russian and French press. The proposed methodology is based on the analysis of the structure of lexical-semantic fields (LSF) of lexical units included in the discourse, and allows us to achieve technological efficiency in the analysis and formalize the results. As a result of the comparative analysis of the cooccurrence of lexical units within the French- and Russian-language discourses, it was found that the lexical units forming the classes of conditional equivalence have significant differences at the level of the structure of lexical-semantic fields due to the peculiarities of media coverage of the Syrian conflict in Russia and France. The difference at the level of LSF of the same-named units significantly affects the semantics of lexical units and, thus, modifies its pragmatic effect. These data should be taken into account when translating.

Enhancement of Electrical Safe Operation Area of 60 V nLDMOS by Engineering of Reduced Surface Electrical Field in the Drift Region.

To enhance the electrical safe operation area (eSOA) of laterally diffused metal oxide semiconductor (LDMOS) transistors, a novel reduced surface electric field (Resurf) structure in the n-drift region is proposed, which was fabricated by ion implantation at the surface of the LDMOS drift region and by drift region dimension optimization. Technology computer-aided design (TCAD) simulations show that the optimal value of Resurf ion implantation dose 1 × 1012 cm-2 can reduce the surface electric field in the n-drift region effectively, thereby improving the ON-state breakdown voltage of the device (BVon). In addition, the extended n-drift region length of the Ld design also improves device BVon significantly, and is aimed at reducing the current density and the electric field, and eventually suppressing the n-drift region impact ionization. The results show that the novel 60 V nLDMOS has a competitive BVon performance of 106.9 V, which is about 20% higher than that of the conventional one. Meanwhile, the OFF-state breakdown voltage of the device (BVoff) of 88.4 V and the specific ON-resistance (RON,sp) of 129.7 mΩ⋅mm2 exhibit only a slight sacrifice.

Study on interdigital flow field structure and two phase flow characteristics of PEM electrolyzer

Proton exchange membrane (PEM) electrolytic hydrogen production has the advantages of high current density, high operating pressure, wide power regulation range and so on. It has good adaptability to wind and photovoltaic power with high volatility and recognized as an important way to solve the effective utilization of renewable energy. In PEM electrolyzer cell (PEMEC), anode flow field plate plays a crucial role in the process of water electrolysis to produce oxygen, which affects the of gas and liquid transfer. Among them, the channel blockage caused by bubble retention is an important factor limiting the performance of PEMEC. In this paper, an interdigital flow field plate is designed based on the plant leaf vein system. The two-phase flow behaviors within the interdigital flow field channel are studied. The results show that the interdigital flow field plate is superior to the traditional serpentine flow field in terms of electrolytic efficiency and voltage loss. The reaction kinetics rate is accelerated, the overall ohmic resistance is reduced by about 4.8 %, and the hydrogen production is increased by about 9.1 %. The above research can provide guidance for the structural improvement and performance improvement of PEMEC.

Interaction between lateral jet and hypersonic rarefied flow

Reaction control systems (RCS) are commonly utilized in a variety of air vehicles, and they give rise to complex flow phenomena. For flows dominated by shock waves and expansion, such as lateral jets, a significant gradient is formed in the local region of the flow field, resulting in a high local Knudsen number, and the continuum hypothesis is no longer applicable, even if the freestream belongs to near-continuum flow. As a result, multi-scale simulation approaches should be used to capture the interactions between these multi-scale structures and appropriately determine aerodynamic forces. Our earlier work, which used the conserved discrete unified gas kinetic scheme (CDUGKS) for monatomic gas, studied the flow field features of lateral jets and aerodynamic forces on blunt bodies under various rarefied freestream conditions. In this research, the Rykov model is used to expand the CDUGKS suit for diatomic gas flow while taking into account the excitation of molecular rotational energy. The impact on the flow field and aerodynamic forces from four parameters, namely freestream Mach number, jet Mach number, jet pressure ratio, and nozzle position, is thoroughly investigated. The results show that even if the incoming Mach number is different, the flow field structure and aerodynamic properties don't change much when the jet momentum ratio stays the same. The solid wall stagnation point value and local peak also show some linear relationships. The jet pressure ratio mainly affects the expansion characteristics of the jet, such as the influence range on the solid wall. In addition, with an increase in the distance between the nozzle position and the torque reference point, higher control efficiency can be obtained. The study of these aspects will help us comprehend lateral jet flow and provide reference for the design of an air vehicle's RCS.

Controllable synthesis of heterostructured CuO–ZnO microspheres for NO2 gas sensors

Nitrogen dioxide (NO2) sensors experience the drawback of requiring high operating temperatures because of the low charge transfer ability of gas-sensing materials. Herein, an advanced NO2 sensor resistant to interference is designed using the interfacial energy barriers of a hierarchical CuO/ZnO composite. With the benefits of abundant desirable defect features, and the amplification effect of heterojunctions, the sensor based on CuO/ZnO composite with 10% Cu(CH3COO)2·H2O (S2) shows outstanding performance in terms of faster response and recovery time (1.8-fold/1.1-fold), higher response (3.1-fold), and lower power consumption (140℃ decrease) compared to the pristine ZnO sensor. Furthermore, the composite sensor exhibits long-term stability and reproducibility, indicating the potential promise of CuO/ZnO heterojunctions in interference-resistant detection of low-concentration NO2 in real applications. This study not only provides a rational solution to designing advanced gas sensors by tuning the interfacial energy barriers of heterojunctions, but also provides a fundamental understanding of CuO structures in the gas-sensing field.

Incorporating gendered analysis and flexibility in heavy work investment studies: a systematic literature review.

Significant impacts of heavy work investment on employee well-being and organizational performance have prompted its increasing importance as a research topic. The findings about good or evil of these repercussions are nonetheless inconclusive. The intersection of Heavy Work Investment construct with gender has not been explicitly addressed by previous literature review and research. Besides, the relevance of flexibility for women, as one of the key factors for successful work-family balance management, still remains to be analyzed. A literature review on Heavy Work Investment was conducted using the SPAR-4-SLR protocol, wherein 83 articles were selected from a pool of 208 previously identified works. Bibliometric and content analysis techniques were employed, including co-word analysis, to evaluate research production, impact, and trends in the gender perspective within Heavy Work Investment. As a result, a strategic diagram illustrates thematic topics, providing a clear understanding of the field's structure and evolution. Six thematic groups were identified, around work-family conflict as the central theme. The explicit consideration of a gender perspective in literature involves nuanced differences regarding the conclusions of studies with a broader focus. First, the emerging prominence of studies on China and Japan becomes clear with gender as the specific focus of the review, aiming to clarify the experiences women face in more traditional societies with a more decisive division of roles. Second, there is a shift in interest regarding the analysis of Job Demands and Job Resources. Despite the apparent decline in interest in the former, the focus in gender literature clearly shifts toward the side of Job Resources, showing potential for the future. It could be understood that in a context of talent war and employee retention efforts, priority is given to better understanding of facilitating individual and organizational factors for work-life balance, especially for women. Future research areas are identified, including gender differences in organizational support and the impact of flexible work on the work-life balance, providing valuable insights for academia, practitioners, and organizations. The need for more comprehensive cross-cultural and gender research is also made clear.

Effects of the gap ratio on the flow field structures and the aerodynamic performance of an airfoil with ridge ice

Under SLD icing conditions, the ridge ice may appear on the surface of aircraft, which led to the significant aerodynamic deterioration and affected aircraft flight safety. The present study experimentally investigated the effects of the gap ratio on the flow field structures and aerodynamic performance of an airfoil with ridge ice. Detailed measurements were performed in a low-speed reflux wind tunnel by utilizing the Particle Image Velocimetry (PIV) technique and a high-sensitivity six-component balance. The results showed that the maximum lift coefficient, stall angle, and maximum pitch moment coefficient of the airfoil increased as the gap ratio enlarged. At AOA = 10 deg, the separation bubble length decreased by 77 % when the gap ratio changed from 0 to 0.1. Meanwhile, the separation bubble length decreased by 68 % when the gap ratio changed from 0.1 to 0.3. Besides, as the increase of the gap ratio, the average vorticity, turbulent kinetic energy, and Reynolds shear stress in the selected region above the airfoil decreased, while the average velocity increased. In addition, the gap ratio did not have an apparent effect on the transition onset positions and the maximum spanwise vorticity in the flow field.

Advancing railway infrastructure maintenance: Thermodynamic parameter inversion of ballast bed and feasibility assessment of fouling detection via infrared thermography (IRT)

The fouled ballast bed significantly impacts the operational condition of the ballasted track. Timely detection of the fouled ballast bed can greatly reduce maintenance workloads and capital expenditure. This study aims to assess the feasibility of employing infrared thermography (IRT) for detecting fouling. Nonetheless, existing research has been conducted under conditions noticeably different from the actual field. Moreover, the climatic conditions surrounding the ballasted track are beyond control. Hence, this paper innovatively utilized thermodynamic simulation to simulate as many conditions as possible. Firstly, temperatures and external meteorological data were obtained on a newly constructed railway line using an infrared thermal imager, temperature sensors, and a weather station. Thermodynamic inversion models were then established based on field structures to determine crucial thermodynamic parameters. The results demonstrate excellent alignment with the existing literature. Expanding upon this groundwork, the study explored the impact of various meteorological factors and weather conditions on the detection effectiveness of IRT. The results indicate that the solar radiation intensity (S) and air temperature (T) have the most significant effect on the surface temperature of the ballast bed (STB) and the temperature difference between the clean and fouled ballast beds (CF-TD). The rainfall (R) can change the thermodynamic properties of the ballast bed. Without considering R, the higher the S or T, the greater the CF-TD. Specifically, on sunny days, the maximum CF-TD can achieve 3.26 °C, while on cloudy days or at night, it is only 0.79 °C and 0.28 °C, respectively. Furthermore, the impact of wind speed (W) on the CF-TD was found to be disregarded in regions with low wind speeds but significant in regions with high wind speeds. In summary, IRT shows promise for rapid initial assessments of ballast bed conditions on sunny days, particularly following rain. While on cloudy days or at night, higher resolution infrared thermal imagers may be required, or other detection indicators may need to be investigated.

Design of inductive electrostatic boom spray system based on embedded closed electrode structure and droplet distribution test in soybean field.

The large water demand, insufficient deposition on the back of the leaf and the uneven distribution of droplets are the problems of traditional agricultural ground plant protection machinery, which leads to low agricultural control efficiency. Combined with the advantages of electrostatic spray technology and the characteristics of high working efficiency and low probability of droplets drift of ground sprayer, an inductive electrostatic boom spray system based on embedded electrode structure is designed and mounted on a large self-propelled boom sprayer for field testing. Based on the working characteristics of the fan nozzle and the analysis of the theory of charge, the inductive electrostatic spray device is designed. The performance of the device is tested and the rationality of the system design is verified by COMSOL numerical simulations, charge-to-mass ratio, and particle size distribution measurements. The spray deposition scanning software and the Box-Behnken experimental design method are used to analyze the spray droplet deposition rate and coverage density of the sprayer on the front and back of the target leaves. The results show that the embedded closed electrode structure designed in this paper can avoid the problem of electrode wetting, and the electric field generated by it is mainly concentrated in the spray liquid film area, and the intensity reaches 6~7 V/m. At the conventional application height (500 mm), the maximum charge-to-mass ratio is 2.91 mC/kg, and the average particle size is 168.22 μm, which is 12.87% lower than that of ordinary spray, when the spray pressure is 0.3 MPa and the electrostatic voltage is 12 kV. The results of field experiments show that the optimum combination of the working parameters with the spray speed is 8.40 m/s, the spray pressure is 0.35 MPa, the charging voltage is 11.50 kV, the amount of droplet deposition in the lower dorsal area of the blade is 1.44 µL·cm-2. This study can provide a certain basis for the application of electrostatic spray technology in ground sprayers.

Experimental and numerical study on characteristics of wake and vortex structure of cluster personnel

The purpose of this study is to study the characteristics of unsteady flow field caused by human activities in crowded public space. This study analyses the wake and vortex structure characteristics of cluster personnel through experiments and numerical simulations. The wake velocity field and vortex structure of 2 (columns) × 5 (rows) human walking were analysed by experimental measurement and large eddy simulation (LES). Personnel movement is simulated by using the dynamic mesh model of computational fluid dynamics (CFD). The results show that the wake of the leg is fully developed, and the wake end presents a “swallow-tail shaped”. The rear row personnel will make a secondary disturbance to the wake of the front row personnel in the wake of the cluster personnel. Therefore, there will be a process of mutual transformation of large-scale vortices and small-scale vortices in the wake field. In addition, the wake flow significantly affects the diffusion and propagation of respiratory pollutants.

Asymmetry in Uranus' High Energy Proton Radiation Belt

AbstractUranus is one of the least explored planets in our solar system, it exhibits a unique magnetic field structure which was observed by NASA's Voyager 2 mission nearly 50 years ago. Notably, Uranus displays extreme magnetic field asymmetry, a feature exclusive to the icy giants. We use the Boris algorithm to investigate how high energy protons behave within this unusual magnetic field, which is motivated by Voyager 2's observation of lower‐than‐expected high energy proton radiation belt intensities at Uranus. When considering full drift motions of high energy protons around Uranus, the azimuthal drift velocity can vary by as much as 15% around the planet. This results in areas around Uranus where particles will be more depleted (faster drift) and other regions where there is a surplus of particles (slower drift). This could provide a partial explanation for the “weak” proton radiation belts observed by Voyager 2.

Effect of strut schemes on combustion characteristics in innovative combined ramjet engine

The Mach 6-capable turbine based combined cycle engine is a potential first-stage propulsion for TSTO mission. In order to improve thrust-to-weight ratio, an innovative tandem combined ramjet engine-FABRE (Fan Augmented Air-Breathing Ramjet Engine) is designed utilizing a versatile multi-mode combustor working at both high-speed ramjet mode and low-speed turbocharged mode. Employing the strut as mixer and flame holder in multi-mode combustor presents theoretical advantages. Nonetheless, a thorough investigation into its practical feasibility and combustion characteristics is essential. This paper experimentally verifies the feasibility of strut approach in multi-mode combustor at various speeds and evaluates the effects of different strut schemes on flow field structure, thermodynamic characteristics, and combustion performance via simulation. The experimental results affirm that employing the strut scheme as a combustion organization method enables the multi-mode combustor to operate effectively under diverse inflow conditions at both high and low speeds. Simulation results further validate that these strut solutions consistently demonstrate superior combustion performance. Additionally, the influences of the strut geometry on heat release and high-temperature area are highly consistent with its effects on combustion efficiency. At low speed, wider struts lead to increased combustion efficiency, while at high speed, they initially rise before declining with further widening. Regardless of speed, increasing strut slant angle consistently reduces efficiency. At low speed, widening the strut lowers the total pressure recovery coefficient, peaking at 45° with varying strut slant angle. Conversely, at high speed, changes in strut width minimally impact, while increasing strut slant angle reduces the coefficient. These conclusions provide valuable insights for the optimization of combustion organization in the design of combined ramjet engine with a wide range of operating conditions.

Improving All‐Sky Simulations of Typhoon Cloud/Rain Band Structures of NOAA‐20 CrIS Window Channel Observations

AbstractThe Cross‐track Infrared Sounder (CrIS) observations (O) contributed greatly to numerical weather prediction. Further contribution depends on the success of all‐sky data assimilation, which requires a method to produce realistic cloud/rain band structures from background fields (i.e., 6‐hr forecasts), and to remove large biases of all‐sky simulation of brightness temperature (TB) in the presence of clouds. In this study, CrIS all‐sky simulations of brightness temperatures at an arbitrarily selected window channel within Typhoon Hinnamnor (2022) are investigated. The 3‐km Weather Research and Forecasting model with three microphysics schemes were used to produce 6‐hr background forecasts (B). The O − B statistic deviate greatly from Gaussian distribution with large biases in either water clouds, or thin ice clouds, or thick ice clouds within Typhoon Hinnamnor. By developing a linear regression function of three all‐sky simulations of TB from 6‐hr forecasts with three microphysics schemes, the O − B statistics approximate a Gaussian normal distribution in water clouds, thin ice clouds and thick ice clouds. Taking the regression function that is established by a training data set to combine 6‐hr background forecasts at later times, the cloud/rain band structures compared much more favorably with CrIS observations than those from an individual microphysic. Furthermore, the regression coefficients derived from Typhoon Hinnamnor (2022) also work for Typhoon Khanun (2023). The work aims to quantify and remove biases in background fields of TB and generating realistic typhoon cloud/rain band structures in background fields will allow a better description of center position, intensity and size to improve typhoon forecasts.