scholarly journals Thrust Characteristics of Ducted Propeller and Hydrodynamics of an Underwater Vehicle in Control Motions

2021 ◽  
Vol 9 (9) ◽  
pp. 940
Author(s):  
Jiaming Wu ◽  
Yizhe Dou ◽  
Haiyan Lv ◽  
Chenghua Ma ◽  
Le Zhong ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Hybrid Algorithm ◽  
Stokes Equations ◽  
Underwater Vehicle ◽  
Flow Fields ◽  
Dynamic Mesh ◽  
Hydrodynamic Performance ◽  
Main Body ◽  
Sliding Mesh ◽  
Ducted Propellers

A numerical technique to simulate the hydrodynamic behavior of ducted propellers attached to an underwater vehicle traveling under the mutually interacting flow fields of the vehicle and the propellers is proposed; the hydrodynamic performance of the propellers and the hydrodynamic loading on the main body of the vehicle when it is in different kinds of motion is investigated numerically. In the research, 3D geometric models of the duct, propeller, and main body of the vehicle are first constructed according to their geometrical features. A computational fluid dynamics (CFD) technique based on the hybrid algorithm of dynamic mesh-nested sliding mesh is applied to solve the Navier–Stokes equations that govern the fluid motion around the duct, propeller, and main body of the vehicle when it is in motion. These equations are solved numerically with the CFD code Fluent. With the proposed numerical simulation technique, the hydrodynamic characteristics of the thrusts generated by the ducted propellers and the loading on the main body in the vehicle system under the mutually interacting flow fields are observed. The results of our numerical simulation indicate that the hybrid algorithm of dynamic mesh-nested sliding mesh can simulate multiple degrees of freedom of motion in underwater vehicle systems. In different motion states, the main body exerts a significant influence on the investigated flow fields; during the vehicle motions, negative wakes are formed on both sides of the main body, which lead to a decrease in the thrusts generated by the propellers on both sides. The thrust of the middle propeller is greater than that of the normal single one because of the obstructing effect in the tunnel caused by the main body.

Numerical Simulation on Hydrodynamic Behaviors of Ducted Propeller in Yawing Motion of an Underwater Vehicle

2015 ◽  
Author(s):  
Jiaming Wu ◽  
Chengwei Zhang ◽  
Zhijian Ye ◽  
Ying Xu ◽  
Weiwen Feng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Stokes Equations ◽  
Underwater Vehicle ◽  
Integrated System ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Vehicle System ◽  
Ducted Propeller ◽  
Ducted Propellers

A practical approach to simulate hydrodynamic performance of ducted propellers attached in an underwater vehicle under the influence of flow field of the vehicle is proposed, hydrodynamic characteristics of the propeller when the vehicle in a dynamic yawing motion is studied numerically. In the research, 3D geometric models of the duct, propeller and underwater vehicle are first constructed according to their geometrical features. Computational fluid dynamics (CFD) technique based on the finite volume method and multi-sliding mesh technique are applied to solve the Navier-Stokes equations which govern the fluid motions around the duct, propeller and underwater vehicle when the vehicle are in a yawing motion. These equations are solved numerically with the CFD code FLUENT. With the proposed numerical simulation approaches, the hydrodynamic phenomenon of thrusts generated from the ducted propellers in the vehicle system under the flow field influence of the vehicle’s yawing motion are analyzed. Results of our numerical simulation indicate that the influence of flow field caused by the underwater vehicle on the thrusts of the ducted propellers is not negligible; when studying the thrust characteristics of a ducted propeller in an underwater vehicle system, the thrust nature of the propeller can only be evaluated objectively on the condition that the vehicle and the ducted propeller are combined together into an integrated system, and the numerical simulation are conducted in such an integrated system.

Trajectory Following of a Tethered Underwater Robot With Multiple Control Techniques

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Jiaming Wu ◽  
Dongjun Chen
Keyword(s):  
Stokes Equations ◽  
Fluid Motion ◽  
Hydrodynamic Performance ◽  
Control Technique ◽  
Underwater Robot ◽  
Main Body ◽  
Multiple Control ◽  
Control Techniques ◽  
Umbilical Cable ◽  
Ducted Propellers

A three-dimensional hydrodynamics and control model to simulate a tethered underwater robot system is proposed. The fluid motion around the robot main body with control ducted propellers is governed by the Navier–Stokes equations, and multiple sliding mesh technique is applied for the numerical solution of the equations. The governing equation of umbilical cable is based on the Ablow and Schechter method. The six degrees-of-freedom equations of motion for underwater vehicle simulations are adopted to estimate the hydrodynamic performance of the underwater robot. In the model, a hybrid feed-forward and feedback control technique is applied to adjust the length of the umbilical cable, and the incremental proportional-integral-derivative (PID) control algorithm is adopted to regulate the rotating speeds of the ducted propellers. The numerical results indicate that the multiple control techniques applied in this paper are feasible and effective, and adjusting the length of the umbilical cable is largely responsible for the vertical trajectory control to the robot, while regulating the rotating speeds of the propellers plays a leading role in the horizontal trajectory manipulation, the deviation between the designated trajectory and the controlled one is acceptable.

scholarly journals Maneuverability and Hydrodynamics of a Tethered Underwater Robot Based on Mixing Grid Technique

2021 ◽  
Vol 9 (6) ◽  
pp. 561
Author(s):  
Jiaming Wu ◽  
Shunyuan Xu ◽  
Hua Liao ◽  
Chenghua Ma ◽  
Xianyuan Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Computational Cost ◽  
Hydrodynamic Performance ◽  
Underwater Robot ◽  
Main Body ◽  
Control Effect ◽  
Sliding Mesh ◽  
Grid Technique ◽  
Towing Speed ◽  
Ducted Propellers

The maneuverability and hydrodynamic performance of the tethered underwater robot in a uniform flow field is investigated. In this research, a tethered underwater robot symmetrically installed with NACA66 hydrofoils and Ka 4-70/19A ducted propellers around its main body is first constructed. The method of overlapping grid combined with sliding mesh is applied in the numerical simulations, and the principle of relative motion is adopted to describe the hydrodynamic responses of the tethered underwater robot during the robot manipulation. The reliability of the CFD methods applied in this research is verified by experimental results, and the comparison between numerical and experimental ones shows that there is very little difference being found. The numerical results indicate that computational cost due to the research’s large-scale domain can be effectively reduced by the adopted numerical methods, hydrofoils’ control effect is greatly influenced by the towing speeds, and thrusts issued from the ducted propellers are related to the tethered underwater robot’s position and towing speed.

Numerical Simulation Study on the Recovery Process of Autonomous Underwater Vehicle

2021 ◽  
Author(s):  
Weigang Huang ◽  
Donglei Zhang ◽  
Jiawei Yu ◽  
Tao He ◽  
Xianzhou Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Autonomous Underwater Vehicle ◽  
Flow Characteristics ◽  
Recovery Process ◽  
Underwater Vehicle ◽  
Hydrodynamic Performance ◽  
Time Step ◽  
Convergence Test ◽  
Motion Paths

Abstract AUV (Autonomous Underwater Vehicle) recovery is considerably influenced by the nearby flow field and simulations of AUV in different motion paths in the wake of a submarine with a propeller are presented in this paper. A commercial CFD solver STAR CCM+ has been used to research the motion and flow characteristics of AUV, which using the advanced computational continuum mechanics algorithms. The DARPA (Defense Advanced Research Projects Agency) SUBOFF Submarine (L1 = 4.356m) propelled with INSEAN (Italian Ship Model Basin) E1619 propeller is used in this study, and the self-propulsion characteristics of the propeller at an incoming flow velocity of 2.75m/s are obtained through numerical simulation and results are compared with the available experimental data to prove the accuracy of the chosen investigation methodology. A grid/time-step convergence test is performed for verification study. AUV (L2 = 0.4356m) is a smaller-scale SUBOFF without a sail, which approaches the submarine in different motion paths in the submarine wake at a relative speed combined with the dynamic overlapping grid technology. The hydrodynamic performance of the AUV when approaching the submarine and the velocity distribution of the surrounding flow field are analyzed, which provides a useful reference for underwater recovery of the AUV.

Trajectory and Attitude Control of an Underwater Towed Vehicle

2006 ◽  
Author(s):  
Jiaming Wu ◽  
Xuefeng Jin
Keyword(s):  
Numerical Simulation ◽  
Hydrodynamic Model ◽  
Attitude Control ◽  
Fuzzy Controller ◽  
Hydrodynamic Performance ◽  
Control Technique ◽  
Main Body ◽  
Time Step ◽  
Vehicle Simulation ◽  
Control Surfaces

A new concept of control technique to perform operation of trajectory maneuvering to a controllable underwater towed vehicle moving in a designated path with a required attitude is presented. A trajectory and attitude control technique for the towed vehicle is proposed in order to accomplish the vehicle’s trajectory and attitude manipulations. This technique is based on a fuzzy algorithm. The towed vehicle in the research consists of a cylindrical main body equipped with several active horizontal and vertical control surfaces. Numerical simulation on the hydrodynamic and control behavior of the towed vehicle under this control manipulation is conducted based on a fully 3-D hydrodynamic model of an underwater towed vehicle. In the model the governing equation of the towed cable is based on the Ablow and Schechter method. The six-degrees-of-freedom equations of motion for an underwater vehicle simulation proposed by Gertler and Hagen are adopted to estimate the hydrodynamic performance of the towed vehicle. In numerical simulation the deflections of vehicle’s control surfaces are governed by the proposed fuzzy controller to manipulate the vehicle traveling along a 3-D stipulated trajectory configuration and required attitude. The values of the deflections are taken as input parameters for the hydrodynamic model at every time step. The performance of the towed vehicle under different designated trajectory and attitude control manipulations can then be investigated with the hydrodynamic model.

Numerical Simulation of Hydrodynamic Performance of Dolphin Fluke Motion

2018 ◽  
Author(s):  
Rijie Li ◽  
Jiajun Chen ◽  
Yushen Huang ◽  
Liwei Liu ◽  
Xianzhou Wang
Keyword(s):  
Numerical Simulation ◽  
Underwater Vehicle ◽  
Hydrodynamic Performance ◽  
Moving Mesh ◽  
Caudal Fin ◽  
Thrust Generation ◽  
Thrust Characteristics ◽  
Oscillating Motion ◽  
The Relationship ◽  
High Thrust

The dolphins’ cruising, generally, with an extremely high thrust efficiency and low drag, which attracted many researchers’ wide attention. It is hoped that we can improve the hydrodynamic performance of underwater vehicle by studying the thrust characteristics of dolphin’s kick and the relationship between the formation of vortex and the thrust generation. However, previous work is mostly focused on investigation of hydrodynamic performance of dolphin fluke motion with a rigid tail which means that the locomotion of caudal fin is defined only by the oscillating motion, without the chordwise deformation. In this paper, the dolphin’s fluke motion is realized by a flexible caudal fin which is defined by a combination of oscillating motion and chordwise deformation. The simulation of the dolphin fluke motion is achieved by STRA-CCM, and dynamic moving mesh is implemented for different stroke functions. This paper primarily analyzed the thrust characteristics and the formation of vortex of dolphin fluke motion, then compared with the available data from previous work with rigid tail. It can be found that the structure of the vortex generated by the dolphin fluke motion with flexible caudal fin is different from a rigid one. Finally, by analyzing the instantaneous flow condition behind the dolphin caudal fin, it can get the reason why the thrust generated by the flexible caudal fin is larger than rigid one.

Two-Dimensional Numerical Simulation of Vortex Shedding of Multiple Stranded Ropes

2019 ◽  
Author(s):  
Xinxin Wang ◽  
Liuyi Huang ◽  
Yanli Tang ◽  
Fenfang Zhao ◽  
Peng Sun
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Flow Distribution ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Two Dimensional ◽  
Navier Stokes Equation

Abstract The stranded rope is one of the important components of the fishery aquaculture equipment. We investigate the fluid flow through two-dimensional stranded rope by direct simulation of the Navier-Stokes equations. We show that for different kinds of stranded rope structures, there are significant differences in hydrodynamic performance. This paper established a numerical model of unsteady flow past the stranded rope based on the Navier-Stokes equation and Morison formulas to study the hydrodynamic characteristics of three-stranded rope, four-stranded rope, and seven-stranded rope, respectively. The turbulence flow was simulated using Standard k-ε model and Shear-Stress Transport k-ω (SST) model. The flow distribution strongly depends on the Reynolds number, a range of 3,900 and 30,000. With increasing Reynolds number, the alternate eddy formation and shedding were repeated behind the stranded ropes. Such parameters of hydrodynamic characteristics of multiple stranded ropes were calculated as the lift and drag coefficients, and vortex shedding frequencies. The numerical simulation results presented flow performances of different cross sections (a, b, c, d) at different Reynolds numbers. However, Reynolds number has no significant impact on the Strouhal number for the same attack angle of the stranded rope.

Numerical Investigations and Performance Experiments of a Deep-Well Centrifugal Pump With Different Diffusers

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Ling Zhou ◽  
Weidong Shi ◽  
Weigang Lu ◽  
Bo Hu ◽  
Suqing Wu
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Deep Well ◽  
Static Pressure Distribution ◽  
And Performance

In this paper, the design methodology of a new type of three-dimensional surface return diffuser (3DRD) is presented and described in detail. The main goal was to improve the hydrodynamic performance of the deep-well centrifugal pump (DCP). During this study, a two-stage DCP equipped with two different type diffusers was simulated employing the commercial computational fluid dynamics (CFD) software ANYSY-Fluent to solve the Navier-Stokes equations for three-dimensional steady flow. A sensitivity analysis of the numerical model was performed in order to impose appropriate parameters regarding grid elements number and turbulence model. The flow field and the static pressure distribution in the diffusers obtained by numerical simulation were analyzed, and the diffuser efficiency was defined to quantify the pressure conversion capability. The prototype experimental test results were acquired and compared with the data predicted from the numerical simulation, which showed that the performance of the pump with 3DRD is better than that of the traditional cylindrical return diffuser (CRD) under all operating conditions. The efficiency and single-stage head of the pump with 3DRD have been significantly improved compared with the standard DCP of the same class.

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