Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

Sun, Chunya,Song, Baowei,Wang, Peng The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.6

Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as long-range, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

Parametric geometric model and shape optimization of an underwater glider with blended-wing-body

Chunya Sun,Baowei Song,Peng Wang 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.6

Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as longrange, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.

Numerical investigation of tip clearance effects on the performance of ducted propeller

Ding Yongle,Song Baowei,Wang Peng 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.5

Tip clearance loss is a limitation of the improvement of turbomachine performance. Previous studies show the Tip clearance loss is generated by the leakage flow through the tip clearance, and is roughly linearly proportional to the gap size. This study investigates the tip clearance effects on the performance of ducted propeller. The investigation was carried out by solving the Navier-Stokes equations with the commercial Computational Fluid Dynamic (CFD) code CFX14.5. These simulations were carried out to determine the underlying mechanisms of the tip clearance effects. The calculations were performed at three different chosen advance ratios. Simulation results showed that the tip loss slope was not linearly at high advance due to the reversed pressure at the leading edge. Three type of vortical structures were observed in the tip clearance at different clearance size.

Numerical simulations of a horizontal axis water turbine designed for underwater mooring platforms

Wenlong Tian,Baowei Song,James H. VanZwieten,Parakram Pyakurel,Yanjun Li 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.1

In order to extend the operational life of Underwater Moored Platforms (UMPs), a horizontal axis water turbine is designed to supply energy for the UMPs. The turbine, equipped with controllable blades, can be opened to generate power and charge the UMPs in moored state. Threedimensional Computational Fluid Dynamics (CFD) simulations are performed to study the characteristics of power, thrust and the wake of the turbine. Particularly, the effect of the installation position of the turbine is considered. Simulations are based on the Reynolds Averaged Navier- Stokes (RANS) equations and the shear stress transport k-u turbulent model is utilized. The numerical method is validated using existing experimental data. The simulation results show that this turbine has a maximum power coefficient of 0.327 when the turbine is installed near the tail of the UMP. The flow structure near the blade and in the wake are also discussed.

Numerical simulations of a horizontal axis water turbine designed for underwater mooring platforms

Tian, Wenlong,Song, Baowei,VanZwieten, James H.,Pyakurel, Parakram,Li, Yanjun The Society of Naval Architects of Korea 2016 International Journal of Naval Architecture and Oc Vol.8 No.1

In order to extend the operational life of Underwater Moored Platforms (UMPs), a horizontal axis water turbine is designed to supply energy for the UMPs. The turbine, equipped with controllable blades, can be opened to generate power and charge the UMPs in moored state. Three-dimensional Computational Fluid Dynamics (CFD) simulations are performed to study the characteristics of power, thrust and the wake of the turbine. Particularly, the effect of the installation position of the turbine is considered. Simulations are based on the Reynolds Averaged Navier-Stokes (RANS) equations and the shear stress transport ${\kappa}-{\omega}$ turbulent model is utilized. The numerical method is validated using existing experimental data. The simulation results show that this turbine has a maximum power coefficient of 0.327 when the turbine is installed near the tail of the UMP. The flow structure near the blade and in the wake are also discussed.

Conceptual design and numerical simulations of a vertical axis water turbine used for underwater mooring platforms

Tian Wenlong,Song Baowei,Mao Zhaoyong 대한조선학회 2013 International Journal of Naval Architecture and Oc Vol.5 No.4

Energy is a direct restriction to the working life of an underwater mooring platform (UMP). In this paper,a vertical axis water turbine (VAWT) is designed to supply energy for UMPs. The VAWT has several controlled blades,which can be opened or closed by inside plunger pumps. Two-dimensional transient numerical studies are presented to determine the operating performance and power output of the turbine under low ocean current velocity. A standard k-εturbulence model is used to perform the transient simulations. The influence of structural parameters, including foil section profile, foil chord length and rotor diameter, on the turbine performance are investigated over a range of tipspeed-ratios ( TSRs ). It was found that turbine with three unit length NACA0015 foils generated a maximum averaged coefficient of power, 0.1, at TSR = 2.

A kind of balance between exploitation and exploration on kriging for global optimization of expensive functions

Huachao Dong,Baowei Song,Peng Wang,Shuai Huang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5

In this paper, a novel kriging-based algorithm for global optimization of computationally expensive black-box functions is presented. This algorithm utilizes a multi-start approach to find all of the local optimal values of the surrogate model and performs searches withinthe neighboring area around these local optimal positions. Compared with traditional surrogate-based global optimization method, thisalgorithm provides another kind of balance between exploitation and exploration on kriging-based model. In addition, a new search strategyis proposed and coupled into this optimization process. The local search strategy employs a kind of improved “Minimizing the predictor”method, which dynamically adjusts search direction and radius until finds the optimal value. Furthermore, the global search strategyutilizes the advantage of kriging-based model in predicting unexplored regions to guarantee the reliability of the algorithm. Finally,experiments on 13 test functions with six algorithms are set up and the results show that the proposed algorithm is very promising.

Multi-objective optimization design for the multi-bubble pressure cabin in BWB underwater glider

Yanru He,Baowei Song,Huachao Dong 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

In this paper, multi-objective optimization of a multi-bubble pressure cabin in the underwater glider with Blended-Wing-Body (BWB) is carried out using Kriging and the Non-dominated Sorting Genetic Algorithm (NSGA-II). Two objective functions are considered: buoyancyweight ratio and internal volume. Multi-bubble pressure cabin has a strong compressive capacity, and makes full use of the fuselage space. Parametric modeling of the multi-bubble pressure cabin structure is automatic generated using UG secondary development. Finite Element Analysis (FEA) is employed to study the structural performance using the commercial software ANSYS. The weight of the primary structure is determined from the volume of the Finite Element Structure (FES). The stress limit is taken into account as the constraint condition. Finally, Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) method is used to find some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. The best solution is compared with the initial design results to prove the efficiency and applicability of this optimization method.

Multi-objective optimization design for the multi-bubble pressure cabin in BWB underwater glider

He, Yanru,Song, Baowei,Dong, Huachao The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

In this paper, multi-objective optimization of a multi-bubble pressure cabin in the underwater glider with Blended-Wing-Body (BWB) is carried out using Kriging and the Non-dominated Sorting Genetic Algorithm (NSGA-II). Two objective functions are considered: buoyancy-weight ratio and internal volume. Multi-bubble pressure cabin has a strong compressive capacity, and makes full use of the fuselage space. Parametric modeling of the multi-bubble pressure cabin structure is automatic generated using UG secondary development. Finite Element Analysis (FEA) is employed to study the structural performance using the commercial software ANSYS. The weight of the primary structure is determined from the volume of the Finite Element Structure (FES). The stress limit is taken into account as the constraint condition. Finally, Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) method is used to find some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. The best solution is compared with the initial design results to prove the efficiency and applicability of this optimization method.

Shape optimization of blended-wing-body underwater glider by using gliding range as the optimization target

Sun, Chunya,Song, Baowei,Wang, Peng,Wang, Xinjing The Society of Naval Architects of Korea 2017 International Journal of Naval Architecture and Oc Vol.9 No.6

Blended-Wing-Body Underwater Glider (BWBUG), which has excellent hydrodynamic performance, is a new kind of underwater glider in recent years. In the shape optimization of BWBUG, the lift to drag ratio is often used as the optimization target. However this results in lose of internal space. In this paper, the energy reserve is defined as the direct proportional function of the internal space of BWBUG. A motion model, which relates gliding range to steady gliding motion parameters as well as energy consumption, is established by analyzing the steady-state gliding motion. The maximum gliding range is used as the optimization target instead of the lift to drag ratio to optimizing the shape of BWBUG. The result of optimization shows that the maximum gliding range of initial design is increased by 32.1% though an Efficient Global Optimization (EGO) process.