Vibrations of simplified rudder induced by propeller wake

2021 ◽  
Vol 33 (8) ◽  
pp. 083618
Author(s):  
Weipeng Zhang ◽  
Xiaoshen Ning ◽  
Fugeng Li ◽  
Hang Guo ◽  
Shili Sun
Keyword(s):  
Propeller Wake

Effect of the number of blades on propeller wake evolution

2007 ◽  
Vol 44 (3) ◽  
pp. 409-418 ◽  
Author(s):  
Mario Felli ◽  
Giulio Guj ◽  
Roberto Camussi
Keyword(s):  
Propeller Wake

scholarly journals Numerical Investigation of Viscous Flow Velocity Field around a Marine Cavitating Propeller

2014 ◽  
Vol 6 ◽  
pp. 272316 ◽  
Author(s):  
Zhifeng Zhu
Keyword(s):  
Velocity Field ◽  
Bubble Dynamics ◽  
Volume Fraction ◽  
Tip Vortex ◽  
Navier Stokes ◽  
Back Side ◽  
Propeller Blade ◽  
Propeller Wake ◽  
Numerical Predictions ◽  
Hybrid Grid

Velocity field around a ship cavitating propeller is investigated based on the viscous multiphase flow theory. Using a hybrid grid, the unsteady Navier-stokes (N-S) and the bubble dynamics equations are solved in this paper to predict the velocity in a propeller wake and the vapor volume fraction on the back side of propeller blade for a uniform inflow. Compared with experimental results, the numerical predictions of cavitation and axial velocity coincide with the measured data. The evolution of tip vortex is shown, and the interaction between the tip vortex of the current blade and the wake of the next one occurs in the far propeller wake. The frequency of velocity signals changes from shaft rate to blade rate. The phenomena reflect the instability of propeller wake.

scholarly journals Numerical Investigation of Unsteady Cavitation Flow around E779A Propeller in a Nonuniform Wake with an Insight on How Cavitation Influences Vortex

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chengzao Han ◽  
Yun Long ◽  
Xiaorui Bai ◽  
Bin Ji
Keyword(s):  
Relative Vorticity ◽  
Cavitation Flow ◽  
Cavitation Model ◽  
Propeller Wake ◽  
Model Combining ◽  
Baroclinic Torque ◽  
Sst Turbulence Model ◽  
Vorticity Generation ◽  
Cavity Evolution ◽  
Vorticity Transport

In the current study, the turbulent cavitation flow around a marine propeller in a nonuniform wake is simulated with the shear stress transport (k−ω SST) turbulence model combining Zwart–Gerber–Belamri (ZGB) cavitation model. The predicted cavity evolution shows a fairly well agreement with the available experimental results. Important mechanisms of propeller cavitation flow, including side-entrant jet and cavitation-vortex interaction, are analyzed in this paper. Vorticity is found to be mainly located in cavitation regions and the propeller wake during propeller rotating. The unsteady behavior of cavitation and side-entrant jet can both promote local vorticity generation and flow unsteadiness. In addition, it is indicated with the relative vorticity transport equation that the stretching term plays a major role in vorticity transportation, while baroclinic torque and Coriolis force term mainly influence the vorticity distribution along the liquid-vapor interface.

Propeller Wake Sheet Roll-up Modeling in Three Dimensions

1997 ◽  
Vol 41 (01) ◽  
pp. 81-92
Author(s):  
Sangwoo Pyo ◽  
Spyros A. Kinnas
Keyword(s):  
Three Dimensional ◽  
Vortex Sheet ◽  
Experimental Information ◽  
Higher Order ◽  
Three Dimensions ◽  
Tip Vortex ◽  
Propeller Wake ◽  
Wake Interaction ◽  
Radial Circulation ◽  
Wake Sheet

An algorithm for predicting the complete three-dimensional vortex sheet roll-up is developed. A higher order panel method, which combines a hyperboloidal panel geometry with a bi-quadratic dipole distribution, is used in order to accurately model the highly rolled-up regions. For given radial circulation distributions, the predicted wake shapes are shown to be convergent and consistent with those predicted from other methods. Then, a previously developed flow-adapted grid and the three-dimensional wake sheet roll-up algorithm are combined in order to estimate the propeller loading/trailing wake interaction. The complete wake geometry is determined by the method without the need of any experimental information on the shape of the wake. Predicted forces and tip vortex trajectories are shown to agree well with those measured in experiments.

URANS Simulation of an Appended Hull During Steady Turn With Propeller Represented by an Actuator Disk Model

2011 ◽  
Author(s):  
Charles M. Dai ◽  
Ronald W. Miller
Keyword(s):  
Flow Field ◽  
Cross Flow ◽  
Field Measurements ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Complex Flow ◽  
Ship Maneuvering ◽  
Disk Model ◽  
Actuator Disk ◽  
Propeller Wake

This paper reports on the comparison between computational simulations and experimental measurements of a surface vessel in steady turning conditions. The primary purpose of these efforts is to support the development of physics-based high fidelity maneuvering simulation tools by providing accurate and reliable hydrodynamic data with relevance to maneuvering performances. Reynolds Averaged Unsteady Navier Stokes Solver (URANS): CFDSHIPIOWA was used to perform simulations for validation purposes and for better understanding of the fundamental flow physics of a hull under maneuvering conditions. The Propeller effects were simulated using the actuator disk model included in CFDShip-Iowa. The actuator disk model prescribes a circumferential averaged body force with axial and tangential components. No propeller generated side forces are accounted for in the model. This paper examines the effects of actuator disk model on the overall fidelity of a RANS based ship maneuvering simulations. Both experiments and simulations provide physical insights into the complex flow interactions between the hull and various appendages, the rudders and the propellers. The experimental effort consists of flow field measurements using Stereo Particle-Image Velocimetry (SPIV) in the stern region of the model and force and moment measurements on the whole ship and on ship components such as the bilge keels, the rudders, and the propellers. Comparisons between simulations and experimental measurements were made for velocity distributions at different transverse planes along the ship axis and different forces components for hull, appendages and rudders. The actuator disk model does not predict any propeller generated side forces in the code and they need to be taken into account when comparing hull and appendages generated side forces in the simulations. The simulations were compared with experimental results and they both demonstrate the cross flow effect on the transverse forces and the propeller slip streams generated by the propellers during steady turning conditions. The hull forces (include hull, bilge keels, skeg, shafting and strut) predictions were better for large turning circle case as compared with smaller turning circle. Despite flow field simulations appear to capture gross flow features qualitatively; detailed examinations of flow distributions reveal discrepancies in predictions of propeller wake locations and secondary flow structures. The qualitative comparisons for the rudders forces also reveal large discrepancies and it was shown that the primary cause of discrepancies is due to poor predictions of velocity inflow at the rudder plane.

Hydrodynamic and Hydroacoustic Phenomena in the Propeller Wake-Rudder Interaction

2014 ◽  
Author(s):  
Mario Felli ◽  
Silvano Grizzi ◽  
Massimo Falchi
Keyword(s):  
Pressure Fluctuation ◽  
Holistic Approach ◽  
Wall Pressure ◽  
Marine Propeller ◽  
Flow Measurements ◽  
Time Resolved ◽  
Propeller Wake ◽  
Wall Pressure Fluctuation ◽  
Free Running

The present paper describes the major mechanisms underlying the hydroacoustic and hydrodynamic perturbations in a rudder operating in the wake of a free running marine propeller. The study was based on a holistic approach which concerned time resolved visualizations and detailed flow measurements around the rudder as well as wall-pressure fluctuation measurements over the rudder surface, at different deflection angles.

Wake and Loss Analysis for a Double Bladed Swept Propeller

2016 ◽  
Author(s):  
Alexandre Capitao Patrao ◽  
Richard Avellán ◽  
Anders Lundbladh ◽  
Tomas Grönstedt
Keyword(s):  
High Speed ◽  
Energy Analysis ◽  
Complex Geometry ◽  
Analysis Method ◽  
Aircraft Wings ◽  
Loss Analysis ◽  
Propeller Wake ◽  
Induced Drag ◽  
Propeller Blades ◽  
Tip Velocity

Inspired by Prandtl’s theory on aircraft wings with minimum induced drag, the authors introduced a double-bladed propeller, the Boxprop, intended for high-speed flight. The basic idea is to join the propeller blades pair-wise at the tip to improve aerodynamics and mechanical properties compared to the conventional propeller. The rather complex geometry of the double blades gives rise to new questions, particularly regarding the aerodynamics. This paper presents a propeller wake energy analysis method which gives a better understanding of the potential performance benefits of the Boxprop and a means to improve its design. CFD analysis of a five bladed Boxprop demonstrated its ability to generate typical levels of cruise thrust at a flight speed of Mach 0.75. The present work shows that the near tip velocity variations in the wake are weaker for this propeller than a conventional one, which is an indication that a counter rotating propeller designed with a Boxprop employed at the front may exhibit lower interaction noise.

Analysis of the flow field around a rudder in the wake of a simplified marine propeller

2017 ◽  
Vol 814 ◽  
pp. 547-569 ◽  
Author(s):  
Roberto Muscari ◽  
Giulio Dubbioso ◽  
Andrea Di Mascio
Keyword(s):  
Flow Field ◽  
Leading Edge ◽  
The Body ◽  
Tip Vortex ◽  
Tip Vortices ◽  
Propeller Wake ◽  
Instantaneous Flow Field ◽  
The Mean ◽  
Flow Variables ◽  
Interaction Problem

The vortex–body interaction problem, which characterizes the flow field of a rudder placed downstream of a single-blade marine rotor, is investigated by numerical simulations. The particular topology of the propeller wake, consisting of a helicoidal vortex detached from the blade tips (tip vortex) and a longitudinal, streamwise oriented vortex originating at the hub (hub vortex), embraces two representative mechanisms of vortex–body collisions: the tip vortices impact almost orthogonally to the mean plane, whereas the hub vortex travels in the mean plane of the wing (rudder), perpendicularly to its leading edge. The two vortices evolve independently only during the approaching and collision phases. The passage along the body is instead characterized by strong interaction with the boundary layer on the rudder and is followed by reconnection and merging in the middle and far wake. The features of the wake were investigated by the $\unicode[STIX]{x1D706}_{2}$-criterion (Jeong & Hussain, J. Fluid Mech., vol. 285, 1995, pp. 69–94) and typical flow variables (pressure, velocity and vorticity) of the instantaneous flow field; wall pressure spectra were analysed and related to the tip and hub vortices evolution, revealing a non-obvious behaviour of the loading on the rudder that can be related to undesired unsteady loads.

scholarly journals CFD Analysis on Propeller Performance with Propeller Boss Cap Fin

2019 ◽  
Vol 8 (4) ◽  
pp. 9516-9521
Keyword(s):  
Open Water ◽  
Developed Countries ◽  
Design Parameters ◽  
Propeller Wake ◽  
Water Test ◽  
Shaft Torque ◽  
Dynamic Meshing ◽  
Propeller Performance ◽  
Fuel Consumption And Emissions ◽  
Developing And Developed Countries

The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. The present study examined the design parameters of the propeller boss cap fin (PBCF) and hub cap in improving the propeller efficiency. PBCF is the kind of hydrodynamic energy saving device which aims to reduce energy losses associated with propeller hub vortex by fitting fins to the cap of a propeller. The main principles of PBCF is breaking up hub vortex to straighten propeller wake, thus recovering the negative pressure on the cap. This reduces propeller’s rotational losses and produces negative torque to reduce propeller shaft torque and generating thrust. The study focuses on the size of the blades on boss cap and optimizing its geometry using CFD technique. Open Water Test has been modelled using dynamic meshing technology known as overset meshing. Seven variations of PBCF are modelled and tested to estimate the efficiency of the propeller. The obtained results are then compared with the simulation result with the propeller without PBCF arrangements. The propeller characteristics (without PBCF) has been initially validated using overset meshing strategy with the available experimental results. Overset mesh has been used to perform this analysis to give better control over the fluid flow. It has been observed that, the propeller with PBCF, one among seven variations is giving nearly 2.0% more efficient than the propeller without PBCF.

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