Submarine Design Research Articles

Analysis of Depth and Liquid Density Factor at Hydrostatic Pressure Assisted by PhET Simulation

The study has been conducted to analyze the depth factor of liquids and the density factor of liquids assisted by PhET simulation. This research is quantitative descriptive research with data presented descriptively, tables, and graphs. The data is obtained through a simulation of hydrostatic pressure in a PhET simulation. The results show that the relationship between the density of the liquid and the depth of the liquid to the pressure of the liquid is directly proportional. If the density of the liquid and the depth of the liquid are greater, the pressure will also be greater. The application of hydrostatic pressure is seen in the design of submarines which need to take into account the amount of hydrostatic pressure in the sea.

Exploring the Opportunities of Generative Artificial Intelligence in Concept Ship Design

Designing vessels is a complex process requiring the consideration of numerous aspects to develop a successful design. Ship and submarine design often requires the designer to approximate, make assumptions, consider scenarios and imagine how the vessel may be used in operation. Having the ability to consult for feedback or request additional information may be a welcome aid. The onset of Generative AI (GENAI) presents a new opportunity to integrate this resource into the workflows of the concept ship design process. Augmenting the design process could have a positive impact on the outcome of the design, further improving various qualities such as performance, sustainability, equality, diversity and inclusion. Aspects associated with weight groups, payload catalogues, technical analysis and layout set out will be explored to investigate whether GENAI could add value to the design process. A case study will be used to facilitate this investigation, taking note of GENAI’s content throughout the process.

Submarine Maneuvering Performance Analysis: a Study of the Effect of Different Rudder Angle Settings on the Turning Dynamics of SUBOFF Submarine

In the ongoing pursuit of bolstering maritime military capabilities, the optimization and augmentation of submarine performance stand as pivotal objectives within the realm of strategic naval power. Given the exacting operational standards required for submarines to execute vital missions like reconnaissance, stealthy attacks, and tracking, this study leverages Computational Fluid Dynamics (CFD) simulation technology to meticulously analyze and evaluate submarine maneuverability under various rudder angle configurations. Through a thorough examination of a spectrum of simulation results, this study unveils the critical determinants influencing submarine maneuverability and proposes corresponding optimization strategies. The outcomes not only furnish a robust scientific foundation for enhancing submarine maneuvering capabilities but also offer valuable technical insights for advancing overall submarine operational efficacy. The discoveries of this study bear significant practical significance and applicability, guiding submarine design endeavors and fortifying tactical responsiveness in intricate maritime settings.

Research on local sound field intensity control technique in metasurface based on deep neural networks.

The use of tunable metasurface technology to realize the underwater tracking function of submarines, which is one of the hotspots and difficulties in submarine design. The structure-to-sound-field metasurface design approach is a highly iterative process based on trial and error. The process is cumbersome and inefficient. Therefore, an inverse design method was proposed based on parallel deep neural networks. The method took the global and local target sound field feature information as input and the metasurface physical structure parameters as output. The deep neural network was trained using a kernel loss function based on a radial basis kernel function, which established an inverse mapping relationship between the desired sound field to the metasurface physical structure parameters. Finally, the sound field intensity modulation at a localized target range was achieved. The results indicated that within the regulated target range, this method achieved an average prediction error of less than 5 dB for 92.9% of the sample data.

Deep-reinforcement-learning-based hull form optimization method for stealth submarine design

The stealth performance of submarines is closely related to their hull forms. In this study, an optimization method based on Deep Reinforcement Learning (DRL) was developed to design submarine hull forms, aimed at maximizing the stealth performance. The DRL optimization technique relied on the decision-making process of an agent for determining actions resulting in changes in the hull form, using stealth performance as the reward. The stealth performance of the submarine was evaluated through a Target Strength (TS) analysis model. Additionally, functional constraints of the examined hull forms were implemented in the optimization process, including geometric constraints related to the hull form and dynamic stability constraints pertaining to the hydrodynamic maneuvering characteristics. The TS of the final optimized hull form was 6.5 dB lower than that of the base model, indicating remarkable stealth performance and improved maneuverability. These results validated the effectiveness of the proposed DRL-based optimization method.

Development of stealth design systems for advanced submarine hull forms to reduce underwater radiated noise and target strength

The stealth capability of a submarine is the key performance to be considered in submarine design since it is directly related to survivability and operational capability. In this study, a system that can be applied from the conceptual design stage for the submarine shape, including the hull forms and appendages, has been developed by considering the two key components that determine the stealth capability of underwater vessels: underwater radiated noise (URN) and target strength (TS). First, for submarine stealth design considering URN, a design optimization technique was developed that can reduce the high flow noise caused by the interaction between the propeller and the vortex generated in various parts of the hull and appendages. And for submarine stealth design considering TS, shape design technology that can minimize the reflections of active sonar was developed through an evaluation method with high adaptability to shape modifications. Finally, by developing the optimization design procedures that comprehensively cover URN and TS, the optimal shapes and arrangements of sail and rudders that can maximize stealth performance have been derived.

The effect of vortex generators on the hydrodynamic performance of a submarine at a high angle of attack using a multi-objective optimization and computational fluid dynamics

Having a suitable maneuverability is of a high importance in the design of submarines. They should have a proper stability during depth changes and emergency rise which requires patterns in their design. In present study, the optimal design of nature inspired Vortex Generators (VGs) attached to the leading edge of side rudders of DARPA sub-off submarine is studied considering an emergency rise condition. To understand the effect of ideal design of VGs on hydrodynamic performance of the submarine, Computational Fluid Dynamics (CFD) analysis are coupled with Multi-Objective Genetic Algorithm (MOGA). To perform the CFD-based optimizations at angle of attack equal to 30°, 4 input parameters based on geometry and positioning of VGs are considered and the drag and lift coefficients of submarine are set as the objective functions. The results of CFD simulations and the optimization shows that VGs optimal geometry have the properties of L = 0.021315 (m), α = 90°, t = 0.00625 (m) and d = 0.027 (m) which results in the CD and CL of submarine being equal to 0.081005 and 0.058114, respectively. Application of VGs causes an small increase in CD in comparison with main model due to enlargement of stagnation point at the leading-edge. VGs also divide the fluid-flow into two portions, both of which experience an enhancement in their turbulent kinetic energy at the leading-edge. Finally, a sensitivity analysis demonstrates the range of applicability of VGs for all the depth changes.

Анализ психологических проблем, возникающих в период несения боевых служб у экипажей многоцелевых и стратегических подводных лодок США

The article is devoted to the influence of such factors as the rate of operational stress and the environment on the appearance of pathological (clinical) anxiety and depression in the personnel of foreign submarines. 
 It is known that the habitat on underwater objects of any purpose contributes to stress and other psychological problems. Habitat conditions can be described in terms of physical habitability terms that contribute to stress. These include: crowding, noise, insufficient or excessive lighting, extreme temperatures, humidity, poor air quality. These parameters cannot be controlled. In addition, another condition for life will be the coefficient of operational voltage. This indicator determines how often you can dive underwater without harm to health. With an increase in the frequency and duration of trips, stress and other psychological problems increase in a person. People can't solve complex problems. They need to return to a normal psychological and physiological state.
 The paper analyzes the possible psychological consequences for the crews of US SSN and SSBN. The psychological problems that arise during the period of military service among the crews of SSN and SSBN of the United States are considered. What may be of interest to specialists in the field of ergonomics involved in the design and creation of domestic submarines of various classes. As well as representatives of the Navy responsible for training crews for existing and under construction submarines. In connection with the above, the article is relevant.

Application of a Deep Neural Network for Acoustic Source Localization Inside a Cavitation Tunnel

Navigating with low noise is the key capability in the submarine design considerations, and noise reduction is also one of the most critical issues in the related fields. Therefore, it is necessary to identify the source of noise during design stage to improve the survivability of the submarines. The main objective of this research is using the supervised neural network to construct the system of noise localization to identify noise source in the large acoustic tunnel. Firstly, we started our proposed method by improving the Yangzhou’s method and Shunsuke’s method. In the test results, we find that the errors of the both can be reduced by using the min-max normalization to highlight the data characteristics of the low amplitude in some frequency. And Yangzhou’s method has higher accuracy than Shunsuke’s method. Then, we reset the diagonal numbers of the cross spectral matrix in Yangzhou’s method to zero and replace mean absolute error to be the loss function for improving the stability of training, and get the most suitable neural network construction for our research. After our optimization, the error decreases from 0.315 m to 0.008 m in cuboid model test. Finally, we apply our method to the cavitation tunnel model. A total of 100 data sets were used for training, 10 sets for verification, and 5 for testing. The average error of the test result is 0.13 m. For the model test in cavitation tunnel in National Taiwan Ocean University, the length of ship model is around 7 m. And the average error is sufficient to determine the noise source position.

Engine oil enhanced performance with hybrid graphene-SWCNT nanomaterials over a Riga curvy surface

Hybrid graphene nanomaterials and single-wall carbon nanotubes (SWCNTs) saturated in a steady laminar viscous incompressible engine oil over a permeable and stretchable curvy Riga surface are focussed in the present study. The effects of nanoparticle shape factor, nanoparticle volume fraction and thermal radiation towards the non-Newtonian flow are considered. The proposed partial differential governing equations are initially transformed into non-linear ODEs aided with similarity expressions. Subsequently, the numerical MATLAB's bvp4c package is utilized to solve the equations. Then, the parameters' influences on dimensionless velocity and temperature distributions, reduced skin friction coefficient and reduced Nusselt number are presented tabularly and graphically. Hybrid graphene-SWCNTs/engine oil has the least velocity, yet the greatest temperature profile when φ1= 0.04 and φ2= 0.02 are considered. It is also observed that the heat transfer performance enhances as the values of nanoparticle shape factor and thermal radiation increase. The lamina-shape nanomaterials are highly recommended to elevate the heat transfer performance of hybrid graphene-SWCNTs/engine oil for realistic applications. The present hybrid nanofluid flow with consideration of thermal radiation and nanoparticle shape factor allows enhancement in the heat and mass transfer for various engineering, technological and industrial operations especially in the design of submarines, thermal reactors and micro-coolers.

Utilization of two‐equation model for analysis of flow over a moving needle in the presence of magnetic field

AbstractMany applications of the ocean and aerodynamic engineering, like the design of submarines, missiles, aircraft, rockets, and jet engines, involve flow over surfaces. Moreover, several experimental propulsion methods for seagoing ships, submarines and aerospace crafts are based on magnetohydrodynamics (MHD). This research explores the MHD boundary layer flow over a moving needle (shaped like a paraboloid of revolution). Governing equations are modelled in cylindrical coordinates under axial symmetry constraint, which is then simplified by employing order of magnitude analysis. In the absence of a magnetic field, these equations are self‐similar, and this analysis is already available in the literature. We have applied the local non‐similarity method to derive the boundary layer equations up to the second level of truncation to compute the solutions of non‐similar boundary layer equations. The built‐in MATLAB routine bvp5c is used to solve these equations numerically. This analysis will assist in predicting flow quantities that are important in designing the objects mentioned above.

Hydrodynamic coefficients of the DARPA SUBOFF AFF-8 in rotating arm maneuver - Part Ⅱ: Test results and discussion

The study of submarine maneuverability is an important part in the overall design of submarines. The goal of this investigation is to study the hydrodynamic coefficients of SUBOFF AFF-8 in rotating arm maneuver. This paper consists of two parts, which deal with the test technology and test results, respectively. Part Ⅱ of this paper presents the angular velocity-dependent derivatives and spatial coupling coefficients of SUBOFF AFF-8 and investigates the forces and moments in steady turn. The forces and moments of SUBOFF AFF-8 are investigated and the hydrodynamic coefficients of SUBOFF AFF-8 are fitted. The results show the coefficients with r in the lower corner represent the linearity of hydrodynamic forces. In order to get more accurate nonlinear coefficients and coupling coefficients, the drift angle should not be too small in the rotating arm test. When SUBOFF AFF-8 has both drift angle and attack angle, the nonlinear degree of rotation increases sharply, which will bring great difficulties to the measurement of forces and moments.

Fatigue Life Analysis of the Submarine Rudder Stock Mechanism at Arctic Low Temperatures

Under the action of Arctic low temperatures and long-term alternating loads, the fatigue life of the submarine rudder stock mechanism is severely tested. In this paper, the research method of the static strength analysis and fatigue life analysis of the submarine rudder stock mechanism is proposed by combining multibody dynamics, the finite element method, and tests. Based on the three-dimensional model and the motion law of the rudder stock mechanism, a multibody dynamic model is established, and the time history loads of each node of the mechanism are obtained. According to the working temperature range of the submarine rudder stock mechanism in the Arctic, low-temperature tensile tests are carried out. Based on the experimental data, the finite element model is built, and static analysis is carried out. Using the S–N static fatigue design method, fatigue simulation analysis is performed by using nCode DesignLife. The analysis results show that the fatigue life of the submarine rudder stock mechanism decreases significantly when the temperature is reduced from 0 °C to −60 °C. This method can provide a reference for submarine design and life model establishment in the Arctic environment.

Dumbbell-Shaped Damage Effect of Closed Cylindrical Shell Subjected to Far-Field Side-On Underwater Explosion Shock Wave

In naval warfare, underwater explosion (UNDEX) shock waves significantly influence the stability and safety of the pressure hull structure of the equipment. This study investigated the unique dynamic buckling of a closed cylindrical shell subjected to a far-field side-on UNDEX shock wave using a three-dimensional numerical simulation based on acoustic–structural arithmetic. In particular, the flow-field response characteristics, plastic deformation, and yield characteristics of the cylindrical shell were determined under the influence of the UNDEX shock wave. Subsequently, the failure mode of the cylindrical shell was analyzed to propose the dumbbell-shaped damage effect. The results revealed that when the UNDEX shock wave encounters a finite cylindrical shell, the fluid exhibits a perturbation such as pressure division, stress wave deflection, and flow in the surroundings of the circular cylinder. However, the fluid cannot produce a sizeable instantaneous displacement that yields certain strong constraints at both ends of the cylindrical shell. These constraints generate an irregular distribution of the flow field pressure, and the cylindrical shell tends to exhibit an “arch” deformation along the direction of shock wave propagation. Owing to the flow surrounding the circular cylinder, a negative pressure zone is generated in the flow field at both ends of the cylindrical shell, which induces a “sucking disc” shape at both ends of the cylindrical shell and ultimately produces a dumbbell-shaped damage effect. The present findings will aid in the structural design and impact resistance of submarines, unmanned undersea vehicles, and additional equipment under the impact load of the UNDEX.

Hydrodynamic coefficients of the DARPA SUBOFF AFF-8 in rotating arm maneuver: Part I: Test technology and validation

The study of submarine maneuverability is an important part in the overall design of submarines. The goal of this investigation is to study the hydrodynamic coefficients of SUBOFF AFF-8 in rotating arm maneuver. This paper consists of two parts, which deal with the test technology and test results, respectively. In Part I, the measuring and testing technique of the rotating arm test in rotating arm basin of Zhejiang University (ZJU) is presented. The connection between the model and the trailer is completed through a cylindrical strut. A steel base is pre-installed inside the model to connect one end of the strut. The detailed calibration of the six-component balance is presented. The linear hydrodynamic coefficients on the horizontal and vertical plane are obtained and compared with the results of DTRC. The results show that the ZJU test values is reliable. The difference between DTRC and ZJU is within 10%. Some technical details about the rotating arm test are discussed in the conclusion. Part Ⅱ of this paper presents the angular velocity-dependent derivatives and spatial coupling coefficients of SUBOFF AFF-8 and investigates the forces and moments in steady turn.

Submarine hydrodynamics for off-design conditions

Traditionally, submarine hydrodynamic design has focussed mainly on requirements regarding operational range, powering performance and manoeuvring ability for deeply submerged conditions. To improve the effectiveness of the boat, attention is also paid to operating near or at the surface and fortunately, computational tools and experimental methods are available to analyse the performance of submarines at these conditions. To advance submarine hydrodynamics knowledge and tools, DMO and MARIN have conducted a wide variety of bi-lateral or collaborative studies using potential and viscous flow methods and experiments on several submarine hull forms. In this article, several examples are presented of the development and use of hydrodynamic tools available during the design and assessment process of future submarines. These examples range from experimental and numerical studies into at-surface and periscope-depth resistance and powering, periscope-depth manoeuvring, high-fidelity flow around the boat during straight flight and manoeuvring motions, wakes of surface-piercing masts, to depth keeping under waves. It is demonstrated how state-of-the-art studies help in advancing the knowledge on submarine hydrodynamics and improving the overall design of modern submarines.

SEMI-AUTOMATIC DISTRIBUTED SHIP SERVICE SYSTEMS ROUTING FRAMEWORK FOR SUBMARINE EARLY-STAGE DESIGN

Part of the complexity of submarine design is that such needs are typified by extensive and densely engineered distributed ship service system(s) (DS3). Even though submarine early-stage design is the phase to address major DS3 choices in the design process, in initial sizing and submarine synthesis reliance is often made on “past practice” and simple vessel displacement-based weight algorithms. Such an approach not only limits the ability of the concept designer to consider the impact of different DS3 options but also inhibits the opportunity (or necessity) to undertake Requirements Elucidation, specifically for DS3. One of the greatest challenges of DS3 synthesis is the development of the routing model of cables, ducting, and piping which can be time-consuming undertaken in Early-Stage Ship Design (ESSD). Thus, this paper proposes a novel method for early-stage routing of DS3 for a submarine. The approach uses network descriptions of the DS3 topology and computer-aided ship design (CASD) to produce DS3 routing rapidly in ESSD. The usefulness of the approach as an early-stage design tool is demonstrated by using it to design the routing for various DS3 of a conventionally powered submarine.

Technical and Economic Feasibility Analysis of a Conceptual Subsea Freight Glider for CO2 Transportation

This study analyses the technical and economic aspects of a novel subsea freight glider (SFG). The SFG is an excellent replacement for tanker ships and submarine pipelines transporting liquefied CO2. The main aim of the SFG is to ship CO2 from an offshore facility to an underwater well where the gas can be injected; as an advantage, the SFG vehicle may be used to transport all kinds of cargo. The SFG travels below the sea surface, making the vessel weather-independent. The research is divided into two steps. Firstly, the technical feasibility analysis is performed by designing a baseline design with a length of 56.5 m, a beam of 5.5 m, and a cargo volume of 1194 m3. The SFG is developed using DNVGL-RU-NAVAL-Pt4Ch1, which was initially created for military submarine designs. Two additional half-scaled 469 m3 and double-scaled 2430 m3 models are created when the baseline design fulfils the technical requirements. Secondly, the economic analysis is carried out using the freely accessible MUNIN D9.3 and ZEP reports. The economic feasibility analysis is illustrated through a case study with a CO2 transport capacity range of 0.5 to 2.5 mtpa (million tons per annum) and a transport length range of 180 km to 1500 km. The prices of CO2 per ton for the SFG, crew and autonomous tankers, and offshore pipelines are comprehensively compared. According to the results, SFGs with capacities of 469 m3, 1194 m3, and 2430 m3 are technically possible to manufacture. Moreover, the SFGs are competitive with a smaller CO2 capacity of 0.5 mtpa at distances of 180 and 500 km and a capacity of 1 mtpa at a distance of 180 km.

DESIGN FOR AN ALL-ELECTRIC DESIGN FOR SUPPORT IN INITIAL DESIGN USING THE NETWORK BLOCK APPROACH: A SUBMARINE EXAMPLE

The layout of the Distributed Ship Service Systems (DS3) can be a major constraint both on the location of hull berth unit and of transverse bulkheads, with implications for conducting maintenance and so contribute to submarine Sustainability. This paper proposes a new early-stage ship design (ESSD) approach that would aid the designer to consider DS3 features physically and logically much earlier in the design process. The approach is termed the Network Block Approach and combines the advantages of the UCL 3D physically based ship synthesis Design Building Block (DBB) approach and the network-based approach for distributed ship service systems (DS3) synthesis already proposed for naval combatants. The proposed Network Block Approach enables modelling of individual spaces to locate and zone various DS3 components and take account of hull unit boundaries and major bulkheads. The paper discusses the importance of DS3 routing to warship Sustainability through the complexity of a submarine design example and shows how the proposed approach enables this to be explored in ESSD.

Technical–Economic Feasibility Analysis of Subsea Shuttle Tanker

This paper presents the technical and economic feasibility analysis of the subsea shuttle tanker (SST). The SST is proposed as an alternative to subsea pipelines and surface tankers with the primary purpose of transporting CO2 autonomously underwater from onshore facilities to subsea wells for direct injection at marginal subsea fields. In contrast to highly weather-dependent surface tanker operations, the SST can operate in any condition underwater. The technical–economic analysis is performed in two steps. First, the SST’s technical feasibility is evaluated by investigating designs with lower and higher capacities. The purpose is to observe the appearance of technical limits (if present) when the SST is scaled down or up in size. Second, an economic analysis is performed using the well-reviewed cost models from the publicly available Zero Emissions Platform (ZEP) and Maritime Un-manned Navigation through Intelligence in Networks (MUNIN) D9.3 reports. The scenarios considered are CO2 transport volumes of 1 to 20 million tons per annum (mtpa) with transport distances of 180 km to 1500 km in which the cost per ton of CO2 is compared between offshore pipelines, crewed/autonomous tanker ships, and SST. The results show that SSTs with cargo capacities 10,569 m3, 23,239 m3, and 40,730 m3 are technically feasible. Furthermore, the SSTs are competitive for short and intermediate distances of 180–750 km and smaller CO2 volumes of 1–2.5 mtpa. Lastly, it is mentioned that the SST design used the DNVGL Rules for Classification for Naval Vessels, Part 4 Sub-surface ships, Chapter 1 Submarine, DNVGL-RU-NAVAL-Pt4Ch1, which is primarily catered towards military submarine design. It is expected that a dedicated structural design code that is optimized for the SST would reduce the structural weight and corresponding capital expenditure (CAPEX).