Combatant Ships Research Articles

Numerical simulations of the ONRT ship maneuvering in calm water and head waves with the partially rotating grid method

This research delves into the maneuverability aspects of a model-scale ONRT surface combatant ship using Computational Fluid Dynamics (CFD) simulations. A key aspect of this study is the comparison of the actuator disc (AD) model and the partially rotating grid (P) method in calm water, complemented by an in-depth analysis of the P method for simulations in waves. Utilizing these methods, the study investigates the performance of the ship in propeller open water, self-propulsion, and complex maneuvers like turning circle and zig-zag. Key findings highlight the superiority of the P method in closely aligning with experimental data, particularly in capturing complex dynamics of ship maneuvers. This research underscores the critical role of propeller side force in maneuvering simulations, a factor often neglected in simpler models like the AD. Maneuvers in head waves are also examined, revealing the nuanced effects of wave orientation on the stability and maneuverability of the ship. This study highlights the effectiveness of CFD in simulating ship maneuvers and the need for ongoing refinement of these techniques to improve accuracy and reliability.

Bulbous Bow Shapes Effect on Ship Characteristics: A Review

Abstract Hydrodynamic optimization is an effective and robust design method that is indispensable in ship hull form performance. Marine engineering and naval architecture have displayed significant interest in integrating bulbous bows on combatant ships. This review aims to gather and assess the existing knowledge regarding the effects of bulbous bow shapes on the hydrodynamic characteristics of combatant ships in terms of historical background, design principles, and impacts of bulbous bow shapes on ship resistance, ship motion in seaways, squat, and seakeeping performance. The review evaluates the effects of bulbous bow shapes on hull hydrodynamics using computational fluid dynamics (CFD), model testing, and full-scale experiments. The text delves into the complexities of improving hull shape and how the bulbous bow design interacts with many operational factors like draft, speed, and sea conditions. This research offers scholars, naval architects, and marine engineers a comprehensive insight into the intricate effects of bulbous bow shapes on combatant ship performance. It aims to consolidate current material to enhance our comprehension of ship design and operation by identifying knowledge gaps and suggesting future research areas.

An Overview of Digital Engineering Methods for Platform Integration of Power and Energy Systems

US Navy ships, and combatant ships in particular, have requirements for integrated systems that are designed and configured for operational efficiency, redundancy, and survivability. Mission systems today and in the future will not always come with their own energy and many may, at times, require extreme pulse power loads. In addition, the migration away from fossil fuels to hybrid systems with energy storage, or the requirements for autonomous platforms, is challenging our ability to design platforms for these systems. Understanding the interdependencies between components, the systems they support, and the energy domains they are member of is a critical ontological design requirement. This paper will address how we applied digital engineering principles and computer science to the design of ontologies that allow for the modeling of complex operational systems riding on the same shipboard energy network. This system network must support varying levels of detail needed during design while at the same time understanding the impacts of that design on ship system operations and their energy loads over time.

Validation of 4DOF maneuvering coefficients optimization using hydrodynamic force and moment estimated from free-running model test results

The present study concerns validation of data-driven modeling for ship dynamics from free-running model test results, in terms of estimation of hydrodynamic force and moment, maneuvering coefficients, and maneuver simulation results. An estimation method for the hydrodynamic force and moment from the acceleration of a surface combatant model ship is suggested and compared with the conventional ship dynamics modeling. The hull dynamics modeling relates the motion and hydrodynamic force and moment is developed by optimizing maneuvering coefficients which leads to minimum loss function of hydrodynamic force and moment and maneuvering criteria. The maneuvering coefficients of the dynamics model is compared with a conventional system-based dynamics model. Lastly, the maneuvering simulation results are compared to the free-running model test results. The suggested model adequately predicts hydrodynamic force and moment in highly coupled sway and yaw motion.

Matlab Implementation using Holtrop and Mennen Method of Bare Hull Resistance Prediction for Surface Combatant Ship Coupled with CFD

Holtop’s & Mennen’s method is one of the most widely used technique in resistance and powering prediction for tankers, general cargo ships, container ships and combatant surface ships. Holtrop’s Statistical Analysis method is utilized, as in comparison to the other options, more complete and closer to the actual results. The main purpose of this paper is to develop a Matlab application using Holtop’s & Mennen’s method for studying and research the total resistance of DTMB 5415 combatant ship. The solid modelling is developed using Maxsurf. The computational fluid dynamic (CFD) technique is applied to analyze the hydrodynamic behaviour of hull form and predict the total resistance (Rt) to provide a description of the other prediction methods. The simulation process was executed using ANSYS software based on fluid flow (STAR-CCM+) solver. The variation of computational grid used in computation is SST (Shear Stress Transport) coarse and fine mesh size for hull speed up to 32 kn. RT resulted from CFD computation is validated with results from Holtrop that has been developed by Matlab implementation. The larger the grid meshing size, the better the validation of the results. The CFD technique demonstrated good agreement with Holtrop formulae in predicting the (RT) of DTMB 5415

Comparative Investigation of Resistance Prediction for Surface Combatant Ship Model using CFD Modeling

The Multi-Mission Surface Combatant (MMSC) is a highly maneuverable combatant ship capable of littoral and open ocean operations. It was designed to confront modern maritime and economic security threats. The MMSC takes the proven capabilities of the littoral combat ship and the inherent flexibility of the Freedom-variant hull to meet the unique maritime requirements of international navies. Computational fluid dynamics (CFD) is applied to present a method to predict the resistance for new surface combatant ship. First, calculations for a typical benchmark DTMB 5415-24 model are carried out using three different mesh sizes for Froude numbers from 0.10 to 0.48 for the purpose of model validation by Star CCM+. The numerical results are compared with the experimental data and the published CFD solutions in terms of wave field and resistance coefficients for accuracy of the solution parameters. Finally, the method is used to study the influence of Froude number variation on the total resistance and wave pattern for the new combatant ship model under the same conditions. Quantitative agreement between the numerical simulations has been observed. This demonstrates that our CFD model is capable of simulating the steady flow around a ship hull with an acceptable accuracy and thus can be used as a complementary tool to laboratory model tests for ship design and ship hydrodynamic research.

Experimental and CFD Resistance Validation of Naval Combatant DTMB 5415-51 Model

The hull model of the surface combatant DTMB 5415 has been selected as a recommended benchmark naval ship for computational fluid dynamics (CFD) validation for resistance analysis. CFD is used to present a method for predicting surface combatant ship resistance. The resistance calculations of a 3 m DTMB 5415 hull model was compared using experimental and CFD techniques. The bare hull shape experiments were set up and carried out at the towing tank facilities at the Military Technical College's Hydrodynamic Laboratory in Egypt. A benchmark test will ensure that the equipment, procedures, and estimates of uncertainty are adequate. For the purpose of model validation, CFD calculations for a DTMB 5415-51 model are performed using three different mesh sizes for Froude numbers ranging from 0.10 to 0.40. For the same Froude numbers and free model conditions, results from towing tank experiments on the model's resistance, sinkage, and trim are presented. The numerical simulations are quantitatively consistent. The numerical results are compared in terms of wave field and resistance coefficients to determine the accuracy of the solution parameters. As evidenced by the resistance curves, the experimental investigation appears to provide very good agreement, indicating that the CFD model is capable of simulating the steady flow around a ship hull with acceptable accuracy and can thus be used as a supplement to laboratory model tests for ship design and ship hydrodynamic research.

Wiktor Wachtang Łomidze pierwszy oficer Gruzin w Polskiej Marynarce Wojennej

Victor Vakhtang Lomidze was the first Georgian officer to serve in the Polish Navy. A student of the military academy in Tiflis, he defended Georgia against the Bolsheviks in 1921. After the conquest of Georgia he reached Poland via Turkey and Greece, where he volunteered to join the army. He was a first promotion graduate of the Officers’ School of the Navy and as a foreigner, he became a contract officer of the Polish Navy. He served on board of numerous Polish ships and in staffs. On 1 September 1939, taking command of the mine-layer “Gryf”, he saved the ship and its crew. Wounded on 3 September 1939. Not fully recovered, he undertakes, together with Commander Hryniewiecki’s group, one of the most unusual and at the same time mysterious actions of our Navy. He was interned in Latvia, where he made an escape attempt, together with 60 other officers. After it failed, he continued trying to join his fighting colleagues. Through Sweden he finally got to England, where he served in the Polish Navy, training young sailors working in the Navy Leadership and in staffs. Due to his health, he was unable to sail on combat ships. Twice promoted during the war, he fought for a country that was not his homeland and shed blood for it.

Polar Explorer F. A. Matisen (in Commemoration of the 150th Anniversary of His Birth)

This article for the first time offers the detailed biographical materials concerning Fyodor Andreyevich Matisen (1872–1921), polar explorer and naval officer, member of the 1899 Russian-Swedish Spitsbergen grade-measurement expedition on the “Bakan” ship and the Imperial Academy of Sciences’ Russian Polar expedition on the “Zarya” schooner (1900–1903), head of the river expeditions to the mouth of the river Lena that were organized by A. V. Kolchak’s Omsk Government (1919) and by the Soviet Government (1920), and the first commander (1908–1910) of the “Taymyr” icebreaking steamer of the Arctic Ocean Hydrographic Expedition. The article also describes Matisen’s service on the Russian Navy’s combat ships. It is based on the materials from the Russian State Naval Archive, Central State Historical Archive of St. Petersburg, St. Petersburg Branch of the Archive of the Russian Academy of Sciences, and the Russian State Archive of Economics. The article is dedicated to the 150th anniversary of Matisen’s birth.

Modelling and synchronous control for a dual-waterjets propulsion steering system

Waterjet propulsion is increasingly used in both combat and civil ships. In this study, a mechanism analysis-based modelling approach of a dual-waterjets propulsion steering system is presented. Experiments carried out on an experimental platform are used to validate the model system. Then a model-based synchronous control strategy for the dual-waterjets propulsion steering system is developed. The experiment results show that the model-based proportional–integral synchronous control strategy may reduce the synchronization error significantly compared with the reciprocal of the synchronization error driving synchronous control strategy practised on some small ships.

URANSE-Based Numerical Prediction for the Free Roll Decay of the DTMB Ship Model

In the present study, Computational Fluid Dynamics (CFD) is used to investigate the roll decay of the benchmark surface combatant DTMB-5512 ship model appended with bilge keels, sailing in calm water at different speeds (Fr = 0.0, 0.138, 0.2, 0.28 and 0.41) and with different initial roll angles. The numerical simulations are carried out using the viscous flow solver ISIS-CFD of the FINETM/Marine software provided by NUMECA. The solver uses the finite volume method to build the spatial discretization of the transport equation to solve the unsteady Reynolds-Averaged Navier–Stokes equations. Two-phase flow approach is applied to model the air–water interface, where the free surface is captured using the volume of fluid method. The closure to turbulence is achieved by making use of the blended Menter shear stress transport and the explicit algebraic Reynolds stress models. First, a systematic validation against the experimental data at medium speed and initial roll angle of 10° are performed; then, the effect of the initial roll angle and ship speed is later studied. Numerical errors and uncertainties are assessed using grid and time step convergence study based on Richardson Extrapolation method. A special focus on the flow in the vicinity of the bilge keels during the simulation is also investigated and presented in the form of velocity contours and vortical structure formations. The resemblance between the CFD results and experimental data for roll motion and flow characteristics are within a satisfactory congruence; however, some discrepancies are recorded for the over predicted roll amplitudes in the second and, sometimes, the third roll cycle, which appeared mostly in the cases with high initial roll angles.

From Mystery to Memory: The Loss of HMAS Sydney

This paper examines the mystery surrounding the sinking of HMAS Sydney in the Indian Ocean on November 19, 1941, by the German raider SV Kormoran. All hands on HMAS Sydney were lost—645 men; these men’s deaths constituted about one-third of Australia’s naval losses in World War II. This cost was unbelievable and unbearable, and in reaction, Australia’s government initially covered up the ship’s fate, only releasing the news when information about it began to leak from other sources. Further, despite numerous attempts, investigators failed to trace the wreckage of either of the combatant ships until 2008, when the crew of SV Geosounder located first the remains of SV Kormoran and then those of HMAS Sydney, using data derived from decoded records left by the German ship’s captain. The outsized role this episode played in the consciousness of a nation led to creative memorials, both to those who were lost, and to the anguish that the incident caused so many Australians. Initially, memorials followed a traditional pattern of plaques and religious services. In 1991, as the 60th anniversary of Sydney’s loss approached, Australia saw both renewed interest in solving the mystery of its location and in memorializing its loss. This occasion and advances in technologies available meant new types of memorials, often reflecting a sensibility that emphasized the individual dimension. For example, an online Honour Roll supports a display of photographs of those lost and vignettes of the sailors’ lives submitted by family members. As well, the Geraldton HMAS Sydney II Memorial, dedicated in 1998, a complex comprised of structures and artworks that imbue a more personal meaning of the tragedy to visitors. Its design is such that those suffering a loss may find solace in this resource, giving it both public and private appeal.

Redesign KCR 60m Bow with Axe Bow Type To Reduce Ship Resistance

Indonesian Navy continues to build 60 Meter Fast Missile Boat (KCR-60) is one of them and acts as a fast patrol boat and high-speed combatant ship in the archipelago warfare. The bow of the ship is an important part in the design of the ship as well as the bow of the KCR-60, because it is the most stressed, stressed from the waves, with the bow design that has a bow profile like an axe, the slender shape of the waterline is able to reduce the impact waves, increase the efficiency of the inflow rate, reduce the resistance of the vessel received so increase a better speed. This study changed the design of the Conventional Bow KCR-60 into the Axe Bow design concept with numerically calculated the total resistance of the Bow Bow design using the Holtrop method and performed a comparative analysis with the computing program MARIN DESPPC 1999 and Maxsurf Resistance V8i software. The results of this study found the total resistance value of KCR-60 Axe Bow type at 28 Knots speed was 364.2 KN and Conventional Bow type was 374.5 KN, the difference was 10.3 kN or 2.75% smaller than the Conventional Bow type in the analysis comparison of Maxsurf Resistance V8i software. For comparative analysis of the MARIN DESPPC 1999 program the total resistance value of the KCR-60 Axe Bow concept at 28 Knots is 283.6 KN and the Conventional Bow type is 288.1 KN, the difference is 4.5 KN 1.56% smaller than the Conventional type.

СТВОРЕННЯ ДВИГУНІВ ПІДВОДНИХ ЧОВНІВ НА ВІТЧИЗНЯНИХ ТЕРЕНАХ (ДРУГА ПОЛОВИНА ХІХ – ПОЧАТОК ХХ СТ.)

The article revealed the process of development of engineering decisions on creation of engines for submarines in the second half of XIX – beginning of XX century. The activities of local inventors on the solution of the problem of engine development that would ensure the movement of the submarine, as a special class of combat ships, in surface and underwater position, are reflected. Having started from the pedal and manual drive for the submarines movement, the comprehensively designers improved the engines, creating and installing gasoline and kerosene motors, electric motors and diesel engines, which provided an increase in radius of boats.

Electromagnetic Wave Absorbing Materials on Radar Frequency Range

Radar absorbing material (RAM) is a material that which can absorb and reduce energy of electromagnetic wave. Recently, RAMs are widely used as an isolator to protect electromagnetic wave interference (EMI) caused by external electromagnetic field and electromagnetic waves generated by radio frequency (RF) components that disturb the performance of a radio system. Whilest, the most strategic function is as anti-radar coating material to supply the needs of military systems such as aircraft, combat ships and other equipments. Generally, RAM must be resistive, magnetic and dielectric. Absorption at the resonant frequency region is indicated by the permitability and permeability values of the material. The Most literature has reported that the basic material which has the potential to absorb electromagnetic waves is ferrite-based magnetic material, namely barium hexaferrite and strontium hexaferrite. Therefore, the current development of research leads to modification and engineering of the material structure so that it is expected to obtain the right parameters with a maximum absorption rate. Generally, RAMs construction design are grouped on the impedance matching and resonant absorber types.

Тенденції розвитку військово-морських сил країн-сусідів України за Чорноморським регіоном

During the last decade, events occurred that directly affected the countries of theBlack Searegion. The membership ofBulgariaandRomaniain the North Atlantic Alliance (NATO), the Georgian-Russian conflict, the illegal annexation of theCrimeanPeninsulaby the Russian Federation (RF) and changes in the political vectors of some states led to certain shifts in the balance of forces in the region. The military-political interests of all these countries directly intersect in theBlack Sea, and their naval forces (Navy) are part of the armed forces. That is why the analysis of the development plans of this type of armed forces of the countries of the specified region may reflect their interests and intentions for the future. The most informative indicator of the prospects for the development of the Navy is the process of re-equipping combat ships, which directly affects the effectiveness of this type of armed forces. The purpose of the article is to compile information on the technical re-equipment of the naval personnel of theBlack Sea region, to identify trends in the development of the Navy and to formulate recommendations on how to use them. The general trends in the re-equipment of the naval forces of theBlack Searegion are the predominance of universal specialization of modernized and new ships over ships of narrow specialization; focus on reconnaissance and surveillance, security and guard functions, as well as border functions, in particular, the fight against smuggling and manifestations of piracy. The article summarizes the program of updating the ship composition of the naval forces of the Black Sea region. The general tendencies of re-equipment of the naval personnel of the Navy are determined. The obtained results will be used in the future to determine the overall potential of the armed forces of the countries of the Black Sea region and to predict possible ways for the development of the military-political situation in the Black Sea region.

The Model of Optimal Allocation of Maritime Oil Spill Combat Ships

The paper describes a two-stage method for optimizing the location of marine oil spill combat forces and assessing the costs related to this action at the sea. An optimization problem relates to positioning the oil pollution combat ships in ports in such a way that they are able combat the anticipated number of oil spills in certain positions in the Polish coast of the Baltic Sea area in the shortest possible time. The problem was classified as NP-hard; therefore, in the first stage, an evolutionary algorithm was applied. The main output of the model based on the evolutionary algorithm is the time of arrival of combat ships from the port to the oil spill area, as well as the costs of such operation; this is defined as the aim function. The first stage of the model does not simulate combat pollution action; therefore, the results obtained were treated as approximate. In the second stage, the several best allocations of oil spill response resources obtained in the first stage were used as input to a detailed simulation model of combat action. For each chosen allocation, a number of oil combat action simulations were carried out. The model can be used to create and verify oil pollution contingency plans, and finally increase the sustainability of sea and coastal areas.

Experimental investigation on stability of intact and damaged combatant ship in a beam sea

ABSTRACTThe stability of a damaged ship is influenced especially by ship motions and floodwater behaviour with their interactions. The behaviour of floodwater is highly nonlinear so that a physical experiment is one of the best ways to obtain the assessment of damaged ship behaviour. The present study investigates experimentally on the performance of an intact and damaged combatant vessel DTMB-5415 in beam waves. Ship model is moored at the bow and stern during the tests in regular waves, and damaged opening is located at the starboard midships and two compartments are flooded. It is shown that ingress and egress of floodwater and the interaction between ship behaviour and water surface effect have a significant impact on ship motions and loads acting on the ship.

Experimental study on the combined damage of multi-layered composite structures subjected to close-range explosion of simulated warheads

The main function of the protective bulkhead of a combatant ship is to protect the cabin from being destroyed by anti-ship missiles, which usually invade the interior and explode at close-range, resulting in the combined shock wave and fragment damage on the structures. This paper presents a design for a protective bulkhead in the form of a multi-layered composite structure, which consists of a front plate, front aerogel felt, anti-penetration layer, back aerogel felt, and back plate. Hemispherical-nosed warheads were manufactured and then used to simulate the warhead of semi-armor-piercing anti-ship missiles. The damages sustained by the multi-layered composite structures are investigated experimentally, along with its protective capability after being subjected to close-range explosions of simulated warheads. Additionally, the effects of the explosion posture of the hemispherical-nosed warheads on the structures are studied. Results reveal that combined damage occurs on the front plate, thereby leading to its shear plugging and large depressed deformation. Although the front plate showed resistance against the shock wave, the anti-penetration layer is damaged by fragments. The failure mode of the back plate consists of local perforation and large bending deformation. For the hemispherical-nosed warheads, damages on the axial posture are more serious than those at the radial posture under close-range explosions at the same standoff distance. Compared with the steel structure, the multi-layered composite structures reduce weight by more than 60% under the same anti-penetrating capability.

Seismic and hydroacoustic analysis of four large underwater explosions off the east coast of Florida

During the summer of 2016, the US Navy detonated four large underwater explosions off the east coast of Florida as part of shock wave testing for the Littoral Combat Ships USS Jackson and USS Milwaukee. The water depth at the explosion site is 900 m. Videos of the events provide further insight into the sources. Originally listed as magnitude 3.7 earthquakes in USGS bulletins, the source types were changed to “Experimental Explosion” as the Navy began releasing information to local news stations. These explosions were recorded on US seismic stations to distances of ~2000 km and on the hydroacoustic array at Ascension Island at a distance of ~8100 km. Seismic signals are complex but cepstral analysis reveals a clear bubble pulse period of 1.15 sec, corresponding to source depths of 50 meters. At Ascension the signals arrive at an RMS level of 136 dB at an SNR of 30 dB. We modeled the propagation loss from the source to Ascension using broadband PE and find the propagation loss to be 126 dB. Backing out this loss, we estimate source levels for the two explosions at 262 dB corresponding to explosion yields of 11,000 lbs.