Longitudinal Position Research Articles

Study on the influence of the longitudinal position of fire source and tunnel width on the maximum ceiling gas temperature

Tunnel fires can result in significant damage to both personnel and property due to the high temperature generated. In this research, a set of numerical simulations were carried out to investigate the smoke flow characteristics in a tunnel with a variable placement of the fire source along the longitudinal centerline. The results showed that due to the influence of the width and the location of the fire source, when the fire source is closer to the upstream portal, most of the air supplied for combustion will come from the upstream, and the downstream cold air will be subjected to more intense smoke entrainment, resulting in different supplementary wind speeds on both sides and an inclined flame. Meanwhile, as the fire source moves from the upstream opening towards the center of the tunnel, the flame changes from inclined to vertical, and the air supplied for combustion shifts mostly from the upstream portal to evenly from both sides. The maximum ceiling gas temperature gradually increases to a maximum value in a non-linear pattern. The empirical equations were suggested for estimating the maximum ceiling gas temperature at various longitudinal positions within the tunnel.

The effect of carrier locking position on the dynamic characteristics of gapless miniature linear guideway

The analysis of the load position of the miniature linear guideway is very important for the dynamic friction characteristics of the linear motion equipment. In this paper, a miniature guideway dynamic friction coefficient tester will be designed. And the effect of load position, movement speed, and load on the friction force of linear guideway will be investigated according to the gapless. The experimental results show that the friction force will be dependent on the load position, load, and movement speed. Among them, the lowest frictional load position can be obtained at any speed of movement and load condition, which occurs at the central load position. The main reason for this is that the effect of the moment is minimum. On the same load position and movement speed, then load is proportional to friction. In the case of fixed load and load position, the effect of velocity on friction is positively correlated in the longitudinal offset position. The frictional force is aggravated by the unevenly distributed pressure on the inner ball due to the moment generated by the slider. At the same time, by observing the loading and the inclination angle of the carrier in the experiment with the laser displacement meter, it can be found that the inclination angle also tends to increase when the load increases.

Concentration effect on the vibrational and electronic properties of MgXZn7-XO7 wurtzoids nanostructure via DFT

In the present work, the ternary compound MgxZn7-x O7Wurtzoid with variable Zn and Mg contents was analyzed using density functional theory with B3LYP 6-311G**basis set. The electronic and vibrational properties of MgxZn7-xO7 wurtzoids, were investigated, including energy gaps, bond lengths, spectral properties, such like infrared spectra and Raman. IR and Raman spectra were compared with experimental longitudinal optical modes frequency results. The theoretical results agree well with experiments and previous data. It has been found that the energy gap is increasing with the increased Mg concentration, and that the longitudinal optical position exposes a UV shift movement with an increase in the concentration.

Deltoid Ligament Release for Varus Deformity Correction in Total Ankle Arthroplasty

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) with severe varus ankle deformity is balanced in the coronal plane by releasing medial soft tissue constraints. There are no previous reports examining the impacts of TAA with concomitant release of the deltoid. Progressive talar tilt and progressive collapsing foot deformity were evaluated. Methods: A retrospective review included patients undergoing TAA with confirmed preoperative varus deformity. Patients underwent complete soft tissue release of the deltoid ligament complex. Pre- and post-operative weightbearing radiographs quantified Meary’s angle, lateral talo-1st metatarsal angle, calcaneal pitch, talar coronal alignment, and the lateral distal tibial angle. The primary endpoints were degrees of coronal plane correction, longitudinal arch position, and complication rates. Results: Thirty-two patients were included with median 12.5 month follow-up. Coronal plane alignment and VAS pain scores improved significantly in all patients, and statistical analysis revealed that complete deltoid ligament release had no bearing on calcaneal pitch and Meary’s angle at final follow-up. Posterior tibial tenotomy was performed on 3 (9.3%) patients. Median coronal plane alignment correction averaged 17.5° improvement (X2(2)= 50.358, P<.001) from 19.5° varus (11.2-24.5°) to 2.0° varus (0.5- 3.5°)(P <.001). Two degrees of coronal plane varus alignment without tilt progression (0.6-3.4°)(P <.001) was maintained through follow-up. Final calcaneal pitch of 18.2° (14.4-23.2°) mirrored initial median measurement of 18.3° (15.7-21.1°). No significant differences were found between Meary’s angle measurements at any time points (P=.568). Eight of 32 patients had complications with five requiring further ankle surgery. Conclusion: Complete release of the deltoid ligament may improve coronal malalignment when performing TAA. Release did not lead to radiographic or clinical medial instability, valgus talar tilt, or medial arch collapse.

Assessment of cellulose nanofibers from bolaina blanca wood obtained at three shaft heights

This study evaluated cellulose nanofibers from bolaina blanca wood (Guazuma crinita) obtained at different heights of the longitudinal axis of the shaft of trees from a three-and-a-half-year-old plantation. The wood was subjected to pulping, bleaching and subsequent mechanical milling using a Changsha Samy XYQM-2L planetary ball mill to obtain cellulose nanofibers. The product was characterised using analytical techniques: scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy. Additionally, the degree of polymerisation was determined. The effect of longitudinal position on cellulose nanofibers characteristics was evaluated by comparing means using ANOVA and Kruskal–Wallis statistical tests. The yield of cellulose nanofibers production from the high, middle and basal sections was 32,1 %, 33,6 % and 31 %, respectively. The obtained cellulose nanofibers exhibited a significantly larger diameter for the high zone (84 nm) compared with the middle (75 nm) and basal (69 nm) zones; the length remained above the micrometre range. With respect to degree of polymerisation, a decrease was evidenced with respect to the increase in shaft height; the basal zone exhibited a degree of polymerisation of 300, a significantly higher value than the middle and high zones, which exhibited degree of polymerisation of 249 and 211, respectively. The product showed typical cellulose type I polymorphism and crystallinity indexes of 76 %, 93 % and 96 % for the high, middle and basal sections, respectively. Regarding the thermostability of cellulose nanofibers, the maximum degradation rate of cellulose nanofibers occurred between 335 °C and 341 °C, with cellulose nanofibers from the basal area being the most stable. The adsorption of the methylene blue dye on cellulose nanofibers was evaluated; an efficiency > 60 % was found.

Additively manufactured medical bone screws: an initial study to investigate the impact of lattice-based Voronoi structure on implant primary stability

PurposeThe present study investigates the mechanical properties of three types of Ti6Al4V ELI bone screws realized using the laser powder bed fusion (LPBF) process: a fully threaded screw and two groups containing differently arranged sectors made of lattice-based Voronoi (LBV) structure in a longitudinal and transversal position, respectively. This study aims to explore the potentialities related to the introduction of LBV structure and assess its impact on the implant’s primary stability and mechanical performance.Design/methodology/approachThe optimized bone screw designs were realized using the LPBF process. The quality and integrity of the specimens were assessed by scanning electron microscopy and micro-computed tomography. Primary stability was experimentally verified by the insertion and removal of the screws in standard polyurethane foam blocks. Finally, torsional tests were carried out to compare and assess the mechanical strength of the different designs.FindingsThe introduction of the LBV structure decreases the elastic modulus of the implant. Longitudinal LBV type screws demonstrated the lowest insertion torque (associated with lower bone damage) while still displaying promising torsional strength and removal force compared with full-thread screws. The use of LBV structure can promote improved functional performances with respect to the reference thread, enabling the use of lattice structures in the biomedical sector.Originality/valueThe paper fulfils an identified interest in designing customized implants with improved primary stability and promising features for secondary stability.

Gain self-adjusting single neuron PID control method and experiments for longitudinal relative position of harvester and transport vehicle

To accurately control the longitudinal relative position of a harvester and transport vehicle, such that grain in the harvester can be accurately unloaded into the transport vehicle's granary, this study established a master–slave collaborative harvesting system. Furthermore, this study proposed a calculation method for the longitudinal deviation of two vehicles, analyzed the structure and mathematical model of the hydraulic stepless transmission, identified the proposed stem transfer function of the hydraulic stepless transmission speed, analyzed incremental proportional–integral–derivative (PID), and developed self-adjusting–single-neuron PID control methods. Simulations and field experiments were performed to test the applicability of the proposed system. The experimental results indicated that the maximum overshoot of the longitudinal deviation between the harvester and the transport vehicle did not exceed 0.25 m, the steady-state mean absolute deviation did not exceed 0.08 m, the steady-state maximum deviation did not exceed 0.26 m, and the steady-state standard deviation did not exceed 0.09 m, when the harvester speed was 0.6, 0.8, and 1 m/s. Field-harvesting application experiments showed that the settling time during the alignment process was 13.2 s, and the steady-state maximum deviation was 0.253 m. The grain can be accurately unloaded into the granary of the transport vehicle. These results indicate that the control method and the master–slave collaborative harvesting system proposed in this study can meet the needs of precise collaborative unloading between the harvester and transport vehicle.

Effect of bladder filling status on positioning errors in post-hysterectomy cervical cancer radiotherapy

Objective: To investigate the effect of different bladder filling states on positioning errors in radiotherapy for cervical cancer and obtain the reference range of bladder filling consistency during radiotherapy. Methods: Patients who underwent postoperative radiotherapy for cervical cancer in Nantong Tumor Hospital from October 2018 to December 2019 were selected. According to the bladder filling deviation, they were divided into group A1 (deviation < 20%) and group B1 (deviation ≥ 20%). The bladder filling variations of the two groups were compared with different positioning errors. Group A2 has a positioning error of <0.4 cm, and group B2 has a positioning error of ≥0.4 cm. The reference range of bladder filling consistency during radiotherapy is obtained by analyzing the composition ratio of different positioning errors of bladder filling deviation. Results: This study included 195 patients with cervical cancer. The error of longitudinal and vertical position in group B1 was significantly higher than that in group A1 (0.50 ± 0.34 vs. 0.26 ± 0.22 cm, p < 0.001, and 0.22 ± 0.17 vs. 0.16 ± 0.12 cm, p < 0.001). Compared with group B2, the absolute deviation of bladder filling in group A2 (54.1% ± 54.4% vs. 25.6% ± 22.7%, p < 0.001) was slight. The chi-square test showed significant differences in the proportion of the positioning state of different bladder filling forms (χ 2 = 31.006, p < 0.001). In addition, there was a significant difference in the proportion of stability errors in patients with poor stability in different directions (χ 2 = 118.551, p < 0.001). Conclusion: In patients with cervical cancer fixed in the supine position, a bladder capacity deviation <20% is easier to achieve excellent positioning with, and it can better control the positioning error of radiotherapy and ensure the positioning accuracy of dose distribution to the target area. It can also achieve good tumor treatment effects. This range can be used as a reference for bladder filling consistency in patients with cervical cancer undergoing radiotherapy.

Six-dimensional light-front Wigner distribution of the pion

We study the recently defined six-dimensional light-front Wigner distributions for the pion case. By using the light-cone spectator model, we calculate the Wigner distributions of the unpolarized, longitudinal-polarized, and transversely-polarized quark in the pion. We present the numerical results of six-dimensional light-front Wigner distributions by fixing certain coordinates. The Wigner distributions exhibit a diffraction pattern in the longitudinal position space, in similar to the single slit diffraction in optics. We also present the numerical results of the three-dimensional distributions in the subspace of longitudinal position and transverse position or transverse momentum coordinates. The six-dimensional light-front Wigner distributions not only contain the most complete information of parton distributions in the hadron, but also provide new physical quantities for future measurements.

Investigation of a strain-gauge dynamometer for measuring boundary layer friction force on the wind tunnel wall

A one-component strain-gauge dynamometer with a measuring range of 0-0.33 N was developed and manufactured at the Central Aerohydrodynamic Institute to measure directly the unsteady friction force of the boundary layer on the wall of a wind tunnel at very high Reynolds numbers. The subject of this study is to investigate the static and dynamic characteristics of the dynamometer and its systematic errors. The effects of the temperature, longitudinal, normal, and side forces and position of the longitudinal force application were investigated during the calibration. A block was designed and manufactured to calibrate the dynamometer using the dead weights in a wind tunnel. The calibration was carried out in laboratory conditions to determine friction force in the block. The developed dynamometer is a dynamic system with its own natural frequency of oscillations. The correction for the dynamometer's own dynamics is suggested on the basis of the method developed earlier. To calculate the correction to dynamometer dynamics the mass of the metric part of the dynamometer, its natural frequency in the absence of damping and the damping coeffi cient were determined. The correction is verifi ed by experiment with application of a step force. Effect of static and dynamic temperature components on dynamometer readings is investigated. Corrections are proposed to eliminate the systematic errors due to the effect of temperature on the basis of the previously developed method. It is shown that the side force does not affect the dynamometer readings, while the effect of the normal force is 1.1 % of the main sensitivity coeffi cient. The effect of the static temperature component on the sensitivity coeffi cient of the dynamometer is 0.017 %/°C. The total measurement uncertainty of the friction force dynamometer is estimated – the standard deviation of the measurement results does not exceed 0.076 % of the measurement range and the relative standard deviation of the main sensitivity coeffi cient is 0.03 %. The standard deviation of measurement of the nonstationary friction force will not exceed 0.86 % of the range of the dynamometer in the presence of oscillations of the sensitive element at its natural frequency.

Параметрическая модель синхронного реактивного двигателя с TLA-ротором в установившихся и переходных режимах

There is considerable practical and scientific interest in synchronous reaction motors (SynRM) with TLA rotor. The core of the TLA rotor has a transversal charge, internal slots, and highly saturated areas. The configuration of the rotor slots is complex and diverse. The task to develop a parametric model of the SynRM with a TLA-rotor designed for calculation of steady-state and transient modes of the motor is relevant. The classical parametric model of SynRM based on the theory of two reactions is used. The calculation method for the parameters of the SynRM model with TLA rotor is presented. The method uses the results of field calculation of two static states of the magnetic field. The steady-state conditions of SynRM are calculated according to the engineering formulas derived from the equation of equilibrium stresses in the stator phase. The Park-Gorev equations are used to calculate the transient modes of the SynRM. Field models of the SynRM under study at longitudinal and transverse rotor positions are presented. Main harmonics of magnetic field in the gap and their dependence on armature current are calculated. Formulas to calculate the inductive parameters of armature winding and performance characteristics of SynRM are given. Differential equations to calculate processes in SynRM are given. The parametric model is used to calculate performance characteristics of SynRM, frequency start process, electromechanical process of SynRM operation in case of asymmetric power supply. The calculation results are compared with the results of field simulation of SynRM with TLA rotor in the Ansys Maxwell environment. The classical parametric model of the synchronous machine based on the theory of two reactions allows fast and high-quality analysis of steady-state and transient modes of operation of a synchronous reactive motor with TLA-rotor under various conditions of power supply and mechanical load, including abnormal ones.

Prediction model of sintering bed temperature based on lognormal distribution function: construction and application

The monitoring of sintering bed temperature is crucial for controlling physical and chemical reactions during the sintering process and achieving low carbonization trends. However, accurately monitoring this temperature is challenging due to the "black box" nature of the sintering bed, which includes the sintering trolley and cup. As a result, a theoretical model needs to be developed urgently to predict the sintering bed's temperature profile. In this investigation, we propose a mathematical model that utilizes the characteristic value of the lognormal distribution to estimate indirectly the temperature of the sintering bed based on the measured temperature of the sintering exhaust gas. The sintering exhaust gas temperature and sintering bed temperature conform to the function: T=T0+A2πw⋅te−(ln(t−tc))2w22. To further enhance the accuracy of the sintering bed temperature prediction, the longitudinal positions of the sintering bed were expanded from three points to multiple points, enabling the construction of a temperature prediction function for the entire sinter bed and obtaining a cloud map of the sintering bed temperature. By determining the sintering terminal point and controlling the sintering machine's speed according to the location of the high-temperature region on the cloud map, the performance of the temperature prediction model was optimized. Through an analysis of the mathematical model and construction of the sintering temperature profile, a predictive route of exhaust gas temperature → three-point sintering bed → total sintering bed was established. This predictive method can significantly enhance the understanding of the sintering process and can be employed in industrial plants.

Performance of steel cable-stayed bridges in ship fires, Part II: Influencing factors and mechanisms

In the context of frequent maritime shipment of combustibles and increasing intentional attacks, evaluating the performance of steel cable-stayed bridges subjected to underneath fires is becoming more critical. However, the current understanding does not cover what factors can affect fire damage to steel cable-stayed bridges and in what mechanisms they introduce the impact. This paper focuses on the influential factors in the performance of steel cable-stayed bridges exposed to ship fires. Nineteen fire scenarios with different longitudinal fire positions, fire intensities, fire-floor distances, and wind speeds were simulated using the fire-thermomechanical coupling method proposed in Part I. Results show that the focus of designing steel cable-stayed bridges against ship fires should be determining longitudinal fire positions and environmental wind speeds. Fire intensities and distances from fire surfaces to the girder bottom significantly affect the thermal response of the girder floor, but the caused entire structural response of the bridge is trivial because the holistic averaged stresses of exposed girders in these cases are close.

Intraseasonal and synoptic modulation of diurnal surface solar radiation over Reunion island in the South-West Indian Ocean

Understanding the space-time variability of Surface Solar Radiation (SSR) is mandatory for the prediction and, eventually, the skillful forecasting of photovoltaic energy production. This paper addresses the modulation of local-scale SSR over Reunion, a tropical island in the South-West Indian Ocean, by the leading modes of climate variability influencing both regional-scale and local-scale atmospheric convection and its associated cloud cover. Analyses focus on synoptic (tropical cyclones [TCs], synoptic convective regimes, including Tropical-Temperate Troughs [TTTs]) and intraseasonal (Madden-Julian Oscillation [MJO]) timescales. The SSR intra-daily variability is first assessed by a diurnal classification of SARAH-E satellite SSR data, and it is then related to the climate conditions mentioned above. SSR anomalies are found larger (smaller) on the windward (leeward) side of Reunion and in the summer (winter) season. The island-scale “cloudy” conditions can typically last 1 or 2 days. Nearby TCs can strongly reduce SSR by up to 50% on average, depending on their distances from Reunion, their sizes, and particularly, their longitudinal positions, which is observed for the first time. Nearby TCs are associated with significant negative SSR anomaly when located west of Reunion but with less significant or even positive anomaly when located east of the island. Synoptic convective regimes (the intraseasonal MJO) have a relatively weaker impact on SSR, with a value up to 13% (5%) of the mean value. Potential interactions between these SSR modulators are also investigated to understand better and eventually predict the mechanisms likely to modulate SSR (and thus photovoltaic electricity production) at sub-seasonal timescales.

Numerical Assessment of the Inhomogeneous Temperature Field and the Quality of Heat Extraction of Nb3Sn Impregnated Magnets for the High Luminosity Upgrade of the LHC

The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN foresees the installation of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn-based quadrupole magnets at selected interaction points of the accelerator. The precise knowledge of each magnet's thermal characteristics and heat extraction performance in response to power depositions during both nominal and ultimate conditions is essential in determining safe operating margins. A 2D numerical framework has been developed to systematically assess the temperature distribution in the combined magnet structure-superfluid He system of each magnet and enveloping cold mass using open-source software. Here a full cross-section of a magnet cold mass is modelled, under the power density distribution expected at the most exposed longitudinal position during accelerator operation at an instantaneous luminosity of 5.0x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">34</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , corresponding to the nominal conditions for HL-LHC. Temperature maps and margins are presented for the inner triplet magnets (MQXF) for both horizontal and vertical beam crossing conditions, along with the validation of the design of cold mass cooling channels for heat extraction.

A novel estimation method for weight and center-of-gravity via the aircraft trim data

Aircraft weight and center-of-gravity are significant parameters that affect flight stability and controllability, and unreasonable CG position may cause serious flight accidents. However, there is no airborne sensor can directly measure aircraft weight and center-of-gravity. In view of this, a novel estimation method for weight and center-of-gravity via the aircraft trim data is introduced. Specifically, the trim data calculation process for the aircraft with variable center of mass is given. Then, an inverse interpolation approach based on the binary search algorithm is presented to estimate the aircraft weight and center-of-gravity, and an improved moving average filter is introduced to eliminate the adverse effect on estimation results caused by the high-frequency noise of airborne sensors. Some simulations are given to demonstrate the validity of the proposed estimation method, and it can be drawn from the result that the aircraft longitudinal CG position estimation error is within 0.05 %MAC.

Beyond winglets: evolutionary scaling of flight-related morphology in stick insects (Phasmatodea)

Abstract The first winged insects evolved from a wingless ancestor, but details of the transition to a fully-winged morphology remain unclear. Studying extant pterygotes with partial wings, such as the stick insects (order Phasmatodea), may help us to understand such a transition. Here, we address how a series of flight-related morphological parameters may correlate with flight evolution by studying different phasmids representing a volancy continuum ranging from miniaturized to full-sized wings. Variation in phasmid wing shape, venation, wing mass and the mass of flight muscle can be described by specific scaling laws referenced to wing length and wing loading. Also, the mass distribution of the body-leg system is conserved in spite of a wide range of variation in body shape. With reduced wing size and increased wing loading, the longitudinal position of the wing-bearing thoracic segments is shifted closer to the insects’ centre of body mass. These results demonstrate complex reconfiguration of the flight system during wing morphological transitions in phasmids, with various anatomical features potentially correlated with reduced flight performance attained with partial wings. Although these data represent phasmid-specific features of the flight apparatus and body plan, the associated scaling relationships can provide insight into the functionality of intermediate conditions between wingless and fully-winged insects more generally.

An integrated longitudinal and lateral control strategy for low friction conditions of tractor semi-trailer vehicles

Driving articulated heavy vehicles (AHVs) at high-speeds is complicated due to their unstable motion modes. Accelerated motion trajectory planning is essential for collision avoidance (CA) maneuver in dynamic traffic conditions. This article proposes a new trajectory planning strategy for collision-free and feasible maneuver of a tractor semi-trailer truck in critical conditions in which the truck and the obstacles are moving with non-constant speeds. For this purpose, a convenient optimal practical trajectory for different tire-road frictional conditions, the physical limitation of the tires, and the stability status of the truck is suggested. The main strategy of the trajectory planning is to increase the capability of the control system using the longitudinal and lateral forces of the tires. A robust integrated controller is then proposed to control the longitudinal and lateral directions of the AHV of which the longitudinal controller is configured to track the longitudinal position considering the vehicle stability conditions, and the lateral controller is organized to follow the yaw rate, the lateral position of the tractor, and the articulation angle. The results show that the proposed novel strategy with integrated longitudinal and lateral control has convenient performance in high-speed and low friction conditions as well as normal situations.

Computational simulation study on disturbance of six-rotor UAVs due to ammunition launch

According to the multi-body dynamics theory, we analyzed and derived the influence laws of the ammunition launch angle, launch timing, mounting position, and mass on the stability of unmanned aerial vehicles (UAVs) by establishing a flight dynamics model of a six-rotor UAV in the process of ammunition launch. The analyses indicated that the ammunition launch angle, the longitudinal mounting position, and the multi-round ammunition launch timing significantly affect the disturbance of the UAV. When single-round ammunition is launched, selecting the appropriate ammunition mounting position can reduce the disturbance amplitude of the position of the UAV, and when multi-round ammunition is launched, the launch timing significantly affects the overall stability of the UAV. On the basis of the overall system and ammunition-related parameters, the optimal launch timing for different deployment methods can be derived. Through modeling analysis, we can qualitatively study the stability of the system during ammunition launch, providing a reference for the design of the ammunition launcher structure and the strike timing.

Investigation of the optimum longitudinal single transverse step location for a high-speed craft

One of the crucial aspects of the conceptual design of a stepped planing hull is the prediction of its performance. To improve performance, the prediction of total resistance must become more accurate. In the field of research, both towing tank experiments and numerical analysis may be used to achieve this goal. In this study, experiments were conducted initially to investigate total resistance of a relatively high-speed craft without a transverse step. Later, numerical computations were carried out to validate the experimental results. After it was determined that the test results and CFD methods were in good agreement, the experimental method continued to investigate the resistance properties of the hull with four different configurations to evaluate the optimal longitudinal position of a single transverse step. The ideal longitudinal position of the single transverse step was evaluated based on a similar relatively high-speed hull with a velocity of up to beam Froude number (FrB) 2.56 in this study, focusing on the FrB range between 2.30 and 2.45.