Total Resistance Coefficient Research Articles

Numerical Simulation of Resistance and Flow Field for Submarines near Ice Surface

When a submarine operates in polar regions, the polar environment inevitably impacts its resistance and flow field characteristics, especially when the submarine navigates near the ice surface. This paper investigates the hydrodynamic characteristics of a submarine sailing near the free water surface and the ice surface using computational fluid dynamics (CFD) methods. In order to quantify the impact of ice on the resistance and flow field characteristics of the submarine, the resistance coefficients are calculated for both near ice surface and free surface. The resistance, velocity field, and pressure distribution around the submarine at different depths and speeds are analyzed. The results indicate that the total resistance of the submarine sailing near the ice surface is lower than the free water surface. When the submarine is sailing near the ice surface, its total resistance coefficient decreases with increased submergence depth at a constant Froude number. At a fixed depth, the resistance coefficient also decreases as the Froude number increases. Additionally, when the dimensionless depth relative to the maximum hull diameter (D) exceeds 3.5, it has little effect on the resistance coefficient.

Effects of Homogeneous and Inhomogeneous Roughness on the Ship Resistance

Ship hull roughness can significantly increase the ship resistance. The roughness caused by biofouling attached to the ship hull is not uniform but has a random distribution. The purpose of this study is to investigate how the inhomogeneous surface roughness distribution affects the ship resistance and the various resistance components. The KRISO container ship (KCS) is considered as a case study. To model the inhomogeneous surface roughness, the ship hull is divided into three segments with equal wetted surface area. Combinations of three roughness heights, denoted as P, Q, and R with ks values of 125 μm, 269 μm, and 425 μm, respectively, are considered to obtain homogeneous and inhomogeneous roughness arrangements (PPP, QQQ, RRR, PQR, PRQ, QPR, QRP, RPQ, and RQP). CFD method is utilized in this study, utilizing RANS equations and k-ω SST turbulence model. A VoF method is used to model the free surface. CFD simulation results show that for the homogeneous roughness, the total resistance coefficient CT increases with increasing ks (PPP < QQQ < RRR), as expected. For the inhomogeneous roughness, the friction resistance coefficient CF increases in the order PQR < PRQ < QPR < QRP < RPQ < RQP, consistent with results from earlier studies. In all the cases, the friction resistance (CF) is the dominant component of the total resistance. As Re increases from 2.2 x 109 to 2.7 x 109, the percentage of the friction resistance decreases, while the percentage of the wave resistance increases. The viscous-pressure resistance decreases slightly as Re increases from 2.2 x 109 to 2.7 x 109.

Numerical Analysis and Experimental Validation of Trimaran and Pentamaran Resistance at Various Separation Distances

Trimaran and pentamaran are multihull types with an odd number of hulls, namely three and five hulls, generally consisting of one center hull and two or four side hulls smaller than the center hull, which can reduce ship resistance. The trimaran and pentamaran have a more complex phenomenon than the monohull, because of the interaction between the main hull and the side hull, which causes interference caused by changes in flow velocity, pressure changes, and wave interactions generated by each hull. The objective of this study is to analyze the resistance of trimaran and pentamaran NPL-4b models with transom-symmetrical hull and separation distances, specifically S/L ratios of 0.2, 0.3, and 0.4. Since a more limited base of experience exists for multihull ships, experimental or numerical modeling techniques are essential for designers. Numeric investigations were conducted using Numeca software, and experiments were performed in a towing tank. Both methods follow ITTC procedures. Furthermore, the numerical analysis with CFD simulation modifies the Navier-Stokes equation using the turbulence model k-ꞷ SST to generate the RANS equation so that unsteady fluid flow problems can be calculated. It can be implemented in predicting resistance in Froude numbers (Fr) 0.2 to 0.6 at the systematic series of trimaran and pentamaran hull shapes at the model scale. The simulation results were compared to experimental data to validate the resistance of the ships. Overall, good resistance was produced by the trimaran and pentamaran in the C configuration at an S/L ratio of 0.4 with a total resistance coefficient CT of 6.60 x 10-3 and 7.37 x 10-3, respectively. The two results are in good agreement, both methods have a discrepancy of 3.70 %. Fluctuations influence the resistance in the wetted surface area (WSA), wave interactions between hulls, ship velocity, and wave propagation in the aft hull.

Hydrodynamic Performance Improvement of a Tirhandil Yacht by Stern Form Modifications

This paper presents a comprehensive investigation to improve the hydrodynamic performance of a Tirhandil hull form by modification efforts on the stern region. The form improvement approach combines computational fluid dynamics (CFD) methods with computer-aided design (CAD) systems. The design process for the reference and modified models was carried out by using CAD systems. The hydrodynamic characteristics of the reference hull form were evaluated by employing CFD methods and it was determined that form improvements should be concentrated on the stern region. The modification process was conducted by considering constraints on the design variables in the stern region and the main dimensions of the reference model. A grid independence study was performed to evaluate various grid structures to determine the optimal mesh configuration for the numerical analyses. The SST k-Omega turbulence model was used for the numerical analyses to simulate turbulence structure around the hull form. Achieving around a 13.4% reduction in the total resistance coefficient, the modified model also exhibited decreased wave amplitudes, smoother wave transitions, and a significant reduction or cancellation of shoulder and stern waves.

Numerical modelling of ship-generated solitary waves

A ship sailing at the wave speed in shallow water produces a complex wave pattern including a downstream disturbance in addition to a periodically generated upstream disturbance. The upstream component consists of solitary waves which are generated at the ship bow and emitted forward as soon as the local water depth is sufficiently modified enabling them to bypass the shallow water wave speed limit. Reynolds Averaged Navier-Stokes numerical simulations are carried out to explore this phenomenon in a fully non-linear and viscous virtual towing tank in cases where a ship sails at the waterway centreline as well as off-centreline conditions. Results indicate that friction attains no more than approximately 25 % of the total resistance coefficient, justifying the use of inviscid methods by previous studies in the literature. Water depth may have a significant impact on the frequency and amplitude of ship-generated solitary waves, but the manner in which this occurs is highly sensitive to the width of the waterway.

Investigation of front hydrofoil position influence on the hydrofoil-assisted craft

The hydrofoil is utilized to generate lift force and craft center of gravity (CoG) rise-up, resulting in reduced total resistance and improved performance of hydrofoil-assisted craft. This study focuses on the performance of a hydrofoil-assisted craft equipped with a double front foil and a single rear foil. The position of the front hydrofoil is adjusted by shifting it back and ahead by one chord length in the longitudinal direction to investigate the craft's performance. Various parameters including hydrodynamic resistance, trim angle, CoG rise-up, and hydrofoil pressure coefficient are examined at different volume Froude numbers (Fn∇). The results indicate that the total resistance coefficient exhibits similar behavior across all three states within the Fn∇ range of 0.73–2.2. However, when the Fn∇ is increased to 2.93 and the front hydrofoil is shifted one chord length ahead, a significant increase of 27% in CoG rise-up and 18% in trim angle is observed compared to the base case study. Likewise, a back shift of the front hydrofoil leads to a 54% increase in CoG rise-up and a 30% increase in trim angle.

Study on the Resistance of a Large Pure Car Truck Carrier with Bulbous Bow and Transom Stern

The resistance of a large Pure Car Truck Carrier (PCTC) with a bulbous bow and a transom stern is evaluated in the present paper. Several cases at nine different ship speeds in calm water are simulated and results are compared with the experimental measurements. The maximum relative error is 0.93% at a Froude number (Fr) of 0.209. The total resistance coefficient of the ship in calm water shows a parabolic trend with increasing Fr, and it reaches a minimum value at Fr = 0.1794. Furthermore, the cases of the ship in regular waves with six different wavelengths and three wave heights are simulated. It is observed that the total resistance exhibits a quadratic relationship with the wavelength when the wave height is fixed. The wave-making resistance increases with the increase in wave height at any fixed wavelength, and it reaches a maximum value when the wave-length is 1.2 times the ship length (Lpp). Additionally, we also investigated the resistance in three different sea states at four different speeds. When the significant wave height of irregular waves is the same as regular waves, the wave-making resistance under irregular waves is much smaller than that of the regular waves. All of these results indicate that the bulbous bow and transom stern can reduce the wave-making and residuary resistances, which can provide a useful reference for the subsequent design and manufacturing of related ships.

JUSTIFICATION OF THE DESIGN OF A 3D PRINTER EXTRUDER NOZZLE USING GRANULES AND CUT POLYMER PARTICLES AS INPUTS

The article defines extrusion as a continuous process of converting a solid bulk polymer into a viscous state followed by pushing it through a molding tool. It is emphasized that extruders are one of the most promising types of equipment for processing polymer materials and are used in various industries, including 3D printing. Attention is focused on the fact that one of the important parts of each extrusion unit is the extrusion head. It is the main tool that determines the final shape of extruded products. It is emphasized that the extruder nozzle has a significant impact on the quality of 3D printing. Four parameters characterizing the nozzle are highlighted: its external size, internal structure, diameter of the hole for extruding the polymer, and the material from which it is made, and each is considered in detail. The main physical and mechanical properties of nozzles made of different materials are presented. A classification of nozzles was developed on the basis of the conducted review. The formula for determining the volumetric productivity of a 3D printer extruder is given, depending on the design of its dosing zone and nozzle resistance. An expression for determining the total resistance coefficient of the nozzle is given, which is defined as the sum of the resistance coefficients of individual geometrically simple sections of its internal structure. It is proposed to use in the extruder of a 3D printer that uses granules or crushed polymer particles as raw materials for the construction of nozzles for 3D printers that print with filament. With their use, a new nozzle design for screw extruders was developed and presented. Based on the analysis of the internal structure of nozzles for 3D printers that print with filament and forming devices of plastic processing equipment, the design of the extruder nozzle using a mandrel was developed and presented.

Vertical compressive bearing performance and optimization design method of large-diameter manually-excavated rock-socketed cast-in-place piles

To study the vertical compressive bearing characteristics of large-diameter rock-socketed cast-in-place piles, eight manually-excavated rock-socketed cast-in-place piles were subjected to vertical compressive on-site load and pile stress tests. The test results showed that the load–displacement (Q-s) curves of the eight test piles were all slow-varying, and the settlement of the piles was less than 11 mm, which met the minimum engineering requirements. The unloading rebound rate was between 55 and 75%, and the elastic working properties of the piles were apparent. The pile axial force gradually decreased with depth, and the slope of the axial force distribution curve reached a minimum in the moderately weathered muddy siltstone layer while the pile side friction resistance reached its maximum value. Pile end friction increases with the increase of load. But the pile end resistance was inversely proportional to the single pile length-to-diameter (L/D) ratio and the depth of rock embedment for the pile. The percentage of pile side friction resistance under maximum load was 86%, indicating that these were characteristic friction piles. Based on the test results and the current Chinese code, the friction coefficient of the pile side soil layer η and the total resistance coefficient of the rock-socketed section ζ were introduced. A revision to the calculation equation for the vertical bearing capacity of the rock-socketed cast-in-place pile in the code was proposed, together with an optimization design method for large-diameter rock-socketed cast-in-place piles.

Study of a hull form optimization system based on a Gaussian process regression algorithm and an adaptive sampling strategy, Part II: Multi-objective optimization

Ships have a wide variety of performance specifications and experience complex navigation conditions. Thus, an efficient numerical optimization system for general hull forms must be able to deal with multi-objective optimization problems. Based on a Gaussian process regression (GPR) algorithm and an adaptive sampling strategy, the authors have developed a single-objective optimization system, SBO-MSE + LCB, which is more efficient than the conventional simulation-based design (SBD) optimization system. However, the application of this system to hull form multi-objective optimization problems presents problems such as excessive new samplings, insufficient exploration of new sample points, and unsuitable convergence criteria. To solve the above problems, we first propose an adaptive sampling strategy based on the idea of spatial clustering. The strategy not only effectively controls the number of sampling numbers at each iteration in the SBO-MSE + LCB optimization system but also enables new sample points to achieve the multi-objective efficient exploration of optimal solution sets for optimization. Then, from the perspective of the convergence and diversity of Pareto optimal solution sets, we design adaptive sampling convergence criteria suitable for multi-objective optimization problems. Based on this, we enable the SBO-MSE + LCB optimization system to solve multi-objective optimization problems and verify its applicability with several cases for which the multi-objective mathematical optimization is performed. Finally, we use the SBO-MSE + LCB multi-objective optimization system and the SBD optimization system to optimize the total resistance coefficient of a deep-sea aquaculture vessel at the scantling and ballast drafts. The results show that the optimization efficiency of the SBO-MSE + LCB multi-objective optimization system is improved by 33.33% from the SBD optimization system for similar optimization performance, proving its advantage in efficiency in practical applications.

An experimental and numerical hydrodynamic study on the Argentinian fishing vessels

The purpose of this work is the validation of the hydrodynamic resistance for a small fishing vessel providing more details about the ship’s hydrodynamics. The selected ship is a traditional vessel that has been sailing in Argentina for more than 20 years without a previous numerical resistance evaluation. Because of the absence of previous numerical optimization, the ship might be a non-efficient vessel from a consumption, operating and polluting point of view. For this reason, in order to bring a more detailed evaluation of the flow around this hull, numerical studies are carried out with the open source OpenFOAM code and validated with experimental results obtained at the University of Buenos Aires towing tank. Reynolds Averaged Navier Stokes (RANS) method together with volume of fluid (VOF) are used for the numerical procedure. Once the resistance results are validated, the total resistance coefficient is split into viscous and wave coefficients in order to provide insight into ship hydrodynamics. Pressure distributions on the hull and wave patterns will be also presented for different ship loading conditions, focusing on the flow around the hull that might give information for a future hull optimization.

Study of a hull form optimization system based on a Gaussian process regression algorithm and an adaptive sampling strategy, Part I: Single-objective optimization

Simulation-based design (SBD) is recognized as a hull form optimization method with great advantages, but its development process has exposed two obvious shortcomings: difficulty in uncertainty quantification (UQ) of the surrogate model and inefficiencies when solving large-scale optimization problems. To mitigate these deficiencies, this paper first proposes a UQ method for the surrogate model based on a Gaussian process regression (GPR) algorithm. Mathematical optimization results show that when the number of samples is insufficient, coupling this UQ method into the deterministic optimization process can, to some extent, reduce the uncertainty of the optimization results. The drawback of the SBD over-reliance on the surrogate model for global prediction accuracy is addressed by designing a hull form optimization system that performs the sequential sampling specifically for the region of interest. This method is referred to as sequential sampling-based optimization (SBO). It was combined with the basic properties of a GPR surrogate model, and a variety of adaptive sampling strategies suitable for the SBO optimization system were designed. Mathematical optimization results show that a hybrid optimization system, SBO-MSE + LCB, which uses the adaptive sampling strategy with the maximum squared error (MSE) and the minimum lower confidence bound (LCB) of the GPR surrogate model has the best efficiency when solving single-objective optimization problems. This method was also used for optimization design of the total resistance coefficient of a 130,000-ton deep-sea aquaculture vessel. The results show that the optimization efficiency of the SBO-MSE + LCB optimization system was improved by 46.67% with respect to that of a conventional SBD optimization system when the optimization solutions were similar, hence demonstrating the efficiency advantage of this system in practical applications.

Novel SEConv1D framework for real-time hydrodynamics prediction of the unidentified underwater vehicle

The accurate and rapid prediction of hydrodynamic characteristics greatly affects the monitoring of the manoeuvring performance of unidentified underwater vehicles. This work proposes a novel SEConv1D framework for the hydrodynamics prediction of the unidentified underwater vehicle. Firstly, a novel framework integrated with one-dimensional convolutional neural networks (Conv1D) and a squeeze-and-excitation network (SENet) is proposed. Secondly, a hydrodynamic dataset based on computational fluid dynamics (CFD) is constructed and verified by experiments. Finally, the proposed framework is applied to predict the total resistance coefficient (Cd) of REMUS UUV and SUBOFF AFF-1. The predicted results agree well with experimental results, and the error of Cd between the experimental data and predicted results for REMUS UUV and SUBOFF AFF-1 is less than 3.39% and 1.97%, respectively, which proved that the proposed framework is effective. Compared with those of the most popular networks (i.e., support vector machine, multilayer perceptron, artificial neural network and Conv1D), the mean error of the Cd and friction resistance coefficient (Cf) between the CFD and predicted results is small at only 0.19%, depicting reductions of 91.5%, 85.9%, 66.7% and 40.6%, respectively. The per inference time of the proposed framework is only 0.164 s form the real-time prediction.

Investigating roughness effects on ship resistance in shallow waters

Shallow waters influence the behaviour and performance of a vessel by modifying the local pressure distribution, wave making, and boundary layer thickness. The boundary layer thickness is also influenced by surface roughness. No previous studies have investigated the combined effects of shallow water contributions and roughness on ship resistance. This study aims to fill this knowledge gap in the literature by using Unsteady Reynolds Averaged Navier-Stokes modelling. Results show that the total resistance coefficient increases between approximately 22% and 36% in the presence of roughness depending on the speed and depth-to-draft ratio. The numerical model used shows that pressure resistance grows at a faster pace than frictional resistance and increases its relative contribution to the total when roughness is applied, contrary to deep water cases.

Numerical Study into the Resistance of a Trimaran Hull at Various Longitudinal Spacing

Although the design of trimaran hull has gained popularity at the end of the 20th century, there are few databases available to numerical analysis of trimaran hull. This paper presents a numerical study of the resistance of trimaran hull at various length ratio (S/L) 0.2, 0.3, 0.4 and Froude numbers 0.2 to 0.6 carried out by CFD simulation using FINETM/MARINE by NUMECA software and experimental data. Tri-A has a lower resistance than the trimaran B and C at low Froude number, but at hight Froude number 0.5 and 0.6, the Tri-A has a low resistance than the others. These results are compared with towing tank test data and obtained a lowest difference in the resistance of 0.98 % at TRI-A3. The lowest resistance for the trimaran model is Tri-C5 (Fr=0.6; S/L=0.4) with a total resistance coefficient (CT) of 65.89x10-4, this is due to favorable wave interference with a minimum IF of 0.02. The Interference Factor (IF) follows the same pattern in each configuration, however at maximum Fr, the minimal IF produced on Tri-A3(Fr=0.4; S/L=0.2), Tri-C4 (Fr=0.5; S/L=0.4), and Tri-C5 is 0.22, 0.12, and 0.02, respectively. Where the lowest IF indicates a positive effect because the resistance of the interference hull is lower hull at high speed. The results of this study are expected to be able to strengthen the data base in presenting the effect of interference resistance of the trimaran, which can then be applied directly in determining the magnitude of the ship’s propulsion at the preliminary design stage.

Form Factor Prediction Based on Ship Model Test Data by Statistical Method

The ship model resistance test is carried out on the towing tank with a certain scale to get the total resistance coefficient of the ship model. The value of the ship’s form factor is needed in extrapolation calculations to get the coefficient and total resistance value of a full-scale ship. The form factor can be obtained using the traditional method, namely testing the resistance of the ship model with a Froude Number between 0.1 – 0.2. This method is known as the Prohaska method. Another method or a more modern method is to use multiple linear regression statistics based on the ship model test. We used data from 41 displacement ship model tests conducted at the Hydrodynamics Technology Laboratory (LTH)-National Agency for Research & Innovation (BRIN). Data processing is done through statistical software using the OLS or Robust method which was previously done by transforming predictor variables to enlarge the variety of variables so that a good regression equation is obtained. The resulting form factor regression is a useful tool for predicting the ship’s Effective Power value.

Hydrodynamic Performance of a Catamaran in Shallow Waters

The effects of limited water depth on the hydrodynamic performance of a catamaran with the full-scale dimensions and geometry of a WAM-V 16 unmanned surface vehicle operating in shallow waters are investigated using an incompressible URANS-VOF solver in OpenFOAM®. Simulations of the flow associated with the passage of the catamaran in shallow waters have been conducted for a range of vehicle speed and several shallow to intermediate water depths under free trim and sinkage conditions. The effects of water depth on the resistance and the dynamic motion of the catamaran are characterized. The total resistance coefficient of the catamaran is shown to increase by as much as over 40% at transcritical Froude numbers, close to the critical depth-dependent Froude number (Frh=1.0). The wave system associated with the flow is examined and its relationship to observed impacts on resistance, trim and sinkage are discussed. The effect of limited water depth on Kelvin’s wake angle is characterized in terms of both length and depth Froude numbers and is shown to be in good agreement with theory.

Hull Form Optimization Study Based on Multiple Parametric Modification Curves and Free Surface Reynolds-Averaged Navier–Stokes (RANS) Solver

In this study, the hull form optimization process to minimize resistance of KCS (KRISO containership) at Fn=0.26 is described. The bow hull form of KCS was modified by varying such design parameters as sectional area curve (SAC), section shape, bulb breadth, and bulb height using multiple parametric modification curves devised by the authors. The resistance performances of modified hull forms were analysed by the viscous flow Reynolds-Averaged Navier–Stokes (RANS) solver of WAVIS ver.2.2. With a view to saving computational time during iterative analyses in the optimization process, the sinkage and trim were set to the fixed values which had been obtained for the original hull form with free condition. The validity of such constant sinkage/trim was then verified by conducting analysis for the optimal hull form with free condition. Optimization to minimize the cost function of the total resistance coefficient of model CTM was performed by sequential quadratic programming (SQP), which is one of the gradient-based local optimization methods. Utilization of parallel computing led to the simultaneous calculation of the gradient, thereby speeding up the whole optimization process. At the design speed of 24 knots, the optimal hull yielded CTM reduction by 1.8%, which is extrapolated to 3.1% reduction of effective power PE in full scale.

Parametrization of suppressing hypersonic second-mode waves by transverse rectangular microgrooves

Aiming at delaying boundary-layer transition of hypersonic vehicles, the second-mode wave in the boundary layer of a Mach 6 flat plate is studied. Linear stability theory (LST) and direct numerical simulations (DNS) are used to investigate the discrete modes and the relation between the suppressing effect of second-mode wave and the location of transverse rectangular micro-groove (0.4 mm in width), respectively. The LST results show that vortex/entropy waves cause the branch types of Mack’s second mode and “mode I” modes (usually derived from fast acoustic waves) to change. The DNS results show that the influence of the grooved surface on the base flow depends on the streamwise location (or boundary-layer thickness). As the grooved surface shifts backward (or thickness increases), the influence of intensity on the base flow decreases, and the friction resistance coefficient <inline-formula><tex-math id="M1">\begin{document}$ C{d_{\text{f}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20220851_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20220851_M1.png"/></alternatives></inline-formula>, differential pressure resistance coefficient <inline-formula><tex-math id="M2">\begin{document}$ C{d_{\text{p}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20220851_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20220851_M2.png"/></alternatives></inline-formula> and total resistance coefficient <inline-formula><tex-math id="M3">\begin{document}$ C{d_x} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20220851_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20220851_M3.png"/></alternatives></inline-formula> of the grooved surface also decrease. It is found that the grooves located in front of the synchronization region of the fast mode and slow mode still have an inhibitory effect on the second-mode wave, which is different from the effect of small-sized (micrometer scale) micro-pores reported in the literature. It is also found that the suppression effect on the second-mode wave is best when the grooves are arranged in the vicinity of the maximum growth-rate point or at the location of the synchronization interval of the fast mode and slow mode.

CFD investigation into resistance characteristics of a pusher-barge system in calm water

Prediction of ship’s total resistance of a pusher-barge system has become enormous complexity involving nonlinear-hydrodynamic flows behaviour along their hull forms. Both of empirical and simplified numerical solutions may still lead into inaccurate results due to presence of nonlinear characteristics of the pressure and viscous resistances. The use of a more sophisticated method would obviously necessitate to solve the above problem. This paper presents a Computational Fluid Dynamics (CFD) approach to predict the total ship’s resistance of a pusher-barge system at various barge’s configurations. To achieve such objective, four different configurations of the barge models incorporated with various Froude numbers have been taken into account in the computational simulation. In general, the results revealed that the increase of Froude number (Fr = 0.182 to 0.312) was proportional to the magnitude of RT, RP and RV. Regardless of the various Froude number, the pusher-barge system with a 13BP configuration provides the highest resistance compared to the 12BP and 11BP. In addition, the arrangement of barges in the longitudinal (12BP) and lateral (21BP) configurations produced a significant effect with increases in RT, RP and RV values of 110%, 167.5% and 77.6%, respectively. The possible reason for this is that the increase of the total wetted surface area for 21BP has produced to a proportionally higher amount of the pressure and viscous resistance. Overall study, the numerical results were presented and analysed based on few aspects involved the total resistance and resistance coefficient in terms of pressure and viscous resistance of the pusher-barge system. This analysis provides very valuable information on choosing the most reliable arrangement of pusher-barge system. This analysis provides very valuable information on choosing the most reliable arrangement of pusher-barge system