Numerical Simulation of Water Flow Around Ship with Screw Propeller

This paper outlines development of method for simulation of complex fluid flows having arbitrary motion of free surfaces. The method is based on rectangular grid with dynamic local grid adaptation. For approximation of a curvilinear computational domain boundaries and a free surface the subgrid geometry resolution method is used. The free surface tracking is provided by VOF method.

Using this approach a fluid flow around ship hull is simulated. Calculation is made with and without taking into account screw propeller. Results are compared with experiment.

In this paper we offer an extension of VOF approach (Hirt, Nichols, 1981). It is realized in FlowVision CFD code.

Andrey Aksenov,Victor Pokhilko, Alexander Dyadkin, TESIS Co., Moscow, Russia

Proceedings of ASME PVP: COMPUTATIONAL TECHNOLOGY (CFD)
FOR FLUID/THERMAL/CHEMICAL/STRESS SYSTEMS AND INDUSTRIAL APPLICATIONS,
July 22-26, 2001 Hyatt Regency, Atlanta, Georgia, USA, Page 1/8

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Numerical Simulation of the Aerodynamic Performance of a H-Type Wind Turbine During Self Starting

The aerodynamic performance and the bypass flow field of a vertical axis wind turbine under self-starting are investigated using CFD simulations in this paper.

The influence of pitch angle variations on the performance of the wind turbine during self-starting is presented. A two-dimensional model of the wind turbine with three blades is employed. A commercial software FlowVision is employed in this paper, which uses dynamic Cartesian grid. The SST turbulence model is used for turbulence modeling, which assumes the flow full turbulent. Based on the comparison between the computed time-dependent variations of the rotation speed with the experimental data, the time-dependent variations of the torgue are presented.

Wei Zuo, Shun Kang, Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, China

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Numerical Modeling of Air-Grass Flow and BPF Noise in Lawn Mowers

The noise of domestic machines including lawnmowers becomes an urgent issue. As the technology matures, designers need better tools to predict performance and efficiency of these machines across a wide range of operating conditions and find optimal ways to reduce noise.

Computational fluid dynamics is an increasingly powerful tool which enables designer to better understand all features of unsteady flow in these machines and to find optimal designs providing higher energetic characteristics, better cutting quality and lower pressure pulsation, vibration and noise. Cutting quality linked with evacuation of grass is a key lawnmower characteristic. Due to this fact application of two-phase (air-grass) lawnmower flow model is inevitable in a prediction procedure. The modeling procedure comprises determination of lawnmower average aerodynamic characteristics and CFD-CAA analysis by acoustic-vortex method to predict sound power data. This method is based on splitting the equations of compressible fluid dynamics into two modes – vortex and acoustic Computational approach applied for the vortex mode flow is a “moving body”- technique: The problem is solved in the absolute frame of coordinates and computational grid changes during the blade
passing. Computations can be made in 4 stages: 1) Computation of the incompressible medium with getting average values of energetic parameters; 2) Computation of the incompressible medium for definition the source function of inhomogeneous acoustic-vortex wave equation; 3) Solution of the acoustic-vortex wave equation; 4) Computation of 2-phase flow. In the 3rd stage the pressure pulsation field can be
represented like a sum of acoustic and vortex oscillation. Wave equation is solved relatively to pressure oscillation using an explicit numerical procedure. Zero pulsatory pressure is an initial condition for solution of the wave equation. The local complex specific acoustic impedance is used to define boundary conditions for the acoustical part of the pressure field. Thus the numerical procedure gives pressure pulsations field
and sound power data on blade passing frequencies (BPF). For the 4th stage computations effective grass particle parameters are determined with accounting the stubble effect on flow parameters and particularities of grass particle interaction with rigid surfaces. Results of a lawnmower air-grass flow (grass particle trajectories and concentration) and corresponding BPF sound power data prediction are presented as an example of modeling procedure application.

Sergey Timuchev, UNIPAT

Alexandr Gamarnik, MTD Products

Anton Tsipenko, UNIPAT

Proceedings of FEDSM2007, 5th Joint ASME/JSME Fluids Engineering Conference, July 30-August 2, 2007 San Diego, California USA, Page 1/4

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Numerical and Experimental Study of 3D Unsteady Flow in a Lawn Mower for Prediction of Pressure Pulsation and Noise

Experiments fulfiled in CETIM have shown that tonal blade-passing-frequency (BPF) noise becomes predominant for lawn-mowers with a big rotor diameter. 2-D and 3-D CFD unsteady computations give a clear picture of pseudo-sound perturbation inside the casing of lawn-mower. Method of representation of unsteady motion of compressible fluid with subsonic flow as a sum of vortex mode (pseudo-sound) and acoustical mode (airborne sound) is used to define the sound near field.

Serguei Timouchev, InteRe Co Ltd

Michael Bockhoff, Karine Mones, CETIM, Noise and Vibration Center

Andrey Aksenov, TESIS Ltd.

FAN NOIS 2003, International Symposium Senlis, 23-25, September 2003, Page 1/8

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Numerical 2-D and 3-D Methods for Computation of Internal Unsteady Pressure Field and Sound Near Field of Fans

Due to a current trend of increasing rotational speed and power, the problem of tone noise and pressure pulsation in centrifugal ventilators becomes a more urgent issue. Often the level of tones determines noise characteristics; mainly these are blade-passing frequencies (BPF).

The broadband noise resulting from small-scale turbulent pressure pulsation in ventilators are undertaken using the method based on a representation of non-statonary motion of a compressible medium as a combination of acoustic and vortex modes.

For the analysis of the problem, the 2D code Harmony and the 3D code FlowVision are used.

Serguei Timouchev, InteRe Co Ltd

Jean Tourret, CETIM, Noise and Vibration Center

Goran Pavic, INSA-Lyon, Laboratory of Vibration and Acoustics

Andrey Aksenov, TESIS Ltd.

FAN NOIS 2003, International Symposium Senlis, 23-25, September 2003, Page 1/10

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Modeling Fluid Structure Interaction for Aerospace Applications

An approach for solving Fluid Structure Interaction in aerospace application is presented in this paper. The proposed approach is based on the two-way coupling between CFD code FlowVision and FEA code ABAQUS. The codes are coupled directly without using any 3rd party software or intermediate
structure.

A direct link offers a full control over the load transfer and interpolation error free data exchange between the codes. The direct link is implemented using special meshing techniques (submerged meshes in FlowVision). FE mesh is subtracted from the Cartesian CFD mesh; all links between CFD mesh cell and outside faces of the finite elements are preserved. Node displacements are transferred directly between FlowVision and Abaqus without any interpolations. The above approach is illustrated with simulation of helicopter emergency landing on the water surface (helicopter equipped with flexible landing ballonets). The simulation objective is to estimate maximum loads on the helicopter hull caused by splashdown. The ballonets should absorb some of the impact and decrease acceleration on the helicopter crew. Results of two simulations are compared: helicopter lands on a rigid surface (ground) and on the still water surface (splashdown).

Andrey A. Aksenov, Kirill A. Iliine and Vladimir V. Shmelev

WEST-EAST HIGH SPEED FLOW FIELD CONFERENCE, 19-22, November 2007, Moscow, Russia, Page 1/9

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Improvement of High-Speed Craft Propulsion by Using of Propellers with Shifted Blade Connection on the Hub

The description of the variable pitch propeller (VPP) is presented. An insight into this propeller operation is given. It’s advantages which give the improvement of propulsion of different purpose ship in comparison with the traditional propeller are noted. To be said in the report it is confirmed by example.

 

In the course of VPP design as applied to sea-going ship and to trawler it was widely utilized the program product FlowVision which able to define hydrodynamics characteristics of VPP. The FlowVision is dedicated to flow simulation at high Reynolds number and small changed density. About other settings in FlowVision of VPP you can find in this article.

Leonid I. Vishnevsky, Krylov shipbuilding Research Institute

Anatoy R. Togunjac, Giprorybflot

Andrew V. Pechenuk, Digital Marine Technology Company

International Conference on Fast Sea Transportation, FAST’2005, June 2005, St. Petersburg, Russia, Page 1/4

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Fluid Structure Interaction Analysis Using Abaqus and FlowVision

The proposed fluid-structure interaction (FSI) approach is based on a two-way coupling between finite-element code Abaqus and finite-volume code FlowVision. The FSI simulation is possible due to a unique mesh generation method used in FlowVision.

The method is called Sub-Grid Resolution Method (SGRM). The SGRM connects seamlessly FE and CFD meshes without introducing any intermediate structures into the FSI layer. It allows to link different mesh types with different discretization levels and ensures a fully conservative (no data loss) bi-directional data transfer between structure and fluid simulation domains. The approximation accuracy of the governing equations is maintained in both simulation domains and the FSI layer. Sloshing water in a flexible cylindrical tank is simulated to illustrate the described fluid structure interaction approach.

A. Aksenov, A. Dyadkin, T. Luniewski, V. Pokhilko, Capvidia, Belgium

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Flow Over Cylinder

CFD analysis of flow over a cylinder for different Reynolds Numbers is explained in this paper by using different turbulence models.

 

Gönül Öykü Güngör, Department of Mechanical Engineering

Bilkent University, Ankara, Turkey

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Features of FlowVision and Ansys Software’s Combined Use for the Determination of Stress Conditions in Oil Tanks

During operation of vertical cylindrical tanks for storage of oil and oil products significant quantities of compacted sediments can be formed and accumulated. As a result, tank useful capacity, tank farm turnover are reduced, oil storage cost is increased due to the necessity to put tanks out of operation and perform their cleaning.

There are methods of cost reduction in case of timely removal of forming sediments by using, for example, various screwtype
devices. In order to determine deformed condition of the tanks during washout and mixing of sediments with movable oil jet produced by operation of the screw-type devices, FLOWVISION and ANSYS software systems were applied. The article describes some features of solving the task.

I.E. Lukyanova, V.V. Shmelev, Ufa State Petroleum Technological University, TESIS

Oil and Gas Business, 2007, Page 1/9

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Experimental and Numerical Study of the Effect of Lateral Wind on the Feeder Airship

Feeder is one of the airships of the Multibody Advanced Airship for Transport (MAAT) system, under development within the EU FP7 project. MAAT is based on a modular concept composed of two different parts that have the possibility to join; respectively they are the so-called Cruiser and Feeder, designed on the lighter than air principle.

Feeder, also named ATEN (Airship Transport Elevator Network), is the smaller one which joins the bigger one, Cruiser, also named PTAH (Photovoltaic modular Transport Airship for High altitude),envisaged to happen at 15km altitude.

During the MAAT design phase, the aerodynamic studies of the both airships and their interactions are analyzed. The objective of these studies is to understand the aerodynamic behavior of all the preselected configurations, as an important element in the overall MAAT system design. The most of these configurations are only simulated by CFD, while the most feasible one is experimentally analyzed in order to validate and thrust the CFD predictions. This paper presents the numerical and experimental investigation of the Feeder “conical like” shape configuration. The experiments are focused on the aerodynamic force coefficients and the pressure distribution over the Feeder outer surface, while the numerical simulation cover also the analysis of the velocity and pressure distribution. Finally, the wind tunnel experiment is compared with its CFD model in order to validate such specific simulations with respective experiments and to better understand the difference between the wind tunnel and in-flight circumstances.

A. Suñol, D. Vucinic, S.Vanlanduit,

T. Markova, A. Aksenov, I. Moskalyov, TESIS

World Academy of Science, Engineering and Technology, Vol:76 2013-04-20, Page 273/281

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