the role of simulation in marine and renewable applications · 2011-01-21 · the role of...

The Role of Simulation in The Role of Simulation in Marine and Renewable Marine and Renewable applicationsapplications

The Role of Simulation in The Role of Simulation in Marine and Renewable Marine and Renewable applicationsapplications

Dr Maciej GinalskiDr Maciej Ginalski

Dr Joe Dr Joe LuxmooreLuxmoore

ANSYS Inc.ANSYS Inc.

South Scotland Engineering South Scotland Engineering

Simulation SeminarSimulation Seminar

November 2010November 2010

Dr Maciej GinalskiDr Maciej Ginalski

Dr Joe Dr Joe LuxmooreLuxmoore

ANSYS Inc.ANSYS Inc.

South Scotland Engineering South Scotland Engineering

Simulation SeminarSimulation Seminar

November 2010November 2010

© 2010 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary© 2010 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary

November 2010November 2010November 2010November 2010

• Unequalled Depth

– Best available physics• Turbulence/transition models

• Non-linear structural

– Experienced and responsive technical support staff

• Unparalleled Breadth

ANSYS Offering

© 2010 ANSYS, Inc. All rights reserved. 2 ANSYS, Inc. Proprietary

• Unparalleled Breadth

– Validated CAE solvers across disciplines

• Comprehensive Multiphysics

– Fully Coupled Fluid-Structure Interaction

• Engineered Scalability

– From beginner to advanced users

– From the laptop to the cluster

• Adaptive Architecture

– Unified CAE user environment BMW ORACLE Racing used CFD to predict the effect of

design alternatives on yacht performance.

Modelling Marine Propellers

According to a 2003 study from the University of Delaware, international

commercial and military shipping fleets consume approximately 289

million metric tons of petroleum per year, which is more than twice the

consumption of the entire population of Germany. The ANSYS FLUENT

simulations run on the modified propeller geometry predicted that the

efficiency would increase by 1 percent to 1.5 percent, and physical

experiments confirmed that this was, in fact, the case.

The new

Kamewa CP-A

propeller

from Rolls-

Royce Marine

Propulsion Systems


Contours of pressure coefficient for the XF5 (left) and the new Kamewa CP-A (right). Insets: Photographs of the blade indicating the

locations of the simulation where cavitation is present (noticeable as pitting). ANSYS FLUENT results helped reduce pressure at the

blade root in the CP-A design, indicated by the lack of cavitation erosion present in the CP-A photo.

experiments confirmed that this was, in fact, the case.

Propulsion Systems

For water pumps, marine propellers, and other

equipment involving hydrofoils, cavitation can cause

problems such as vibration, increased hydrodynamic

drag, pressure pulsation, noise, and erosion on solid

surfaces. Most of these problems are related to the

transient behaviour of cavitation structures. To better

understand these phenomena, unsteady 3D simulations

Modeling Cavitation Effects


Courtesy SVA-Potsdam (Potsdam Model Basin)

understand these phenomena, unsteady 3D simulations

of cavitating flow around single hydrofoils are often

performed and the results are compared to experiments.

Unsteady propeller cavitation in the wake of a ship

Mixed Flow Pumps are in-line pumps that generate both axial

and radial flow for applications requiring high through-put and a

low pressure discharge. The steady-state mixing-plane model

is used to simulate the complex motion generated by the

rotating impeller and static guide vanes. Results for pump

performance can be used to predict the behaviour of similar

pumps operating in similar regimes.

The pump

geometry

Propulsion Systems

Mixed Flow Pump


pumps operating in similar regimes.

Jet skis use mixed flow pump technology for propulsion

Velocity vectors on the downstream

side of the pump showing the straightening

effect of the guide vanes

Path lines show

the swirl imposed by the

rotating impeller followed

by the straightening effect

of the guide vanes and

subsequent motion of the

water around the pipe bend

ANSYS Products for

Turbomachinery

GeometryGeometry MeshMesh AnalysisAnalysis

CAD

CAD

ANSYS ANSYS

BladeModelerBladeModeler


ANSYS Workbench

ThroughflowThroughflow

ANSYS BladeModeler

• Two components

– BladeGen

• Aero- or hydrodynamic definition of

blade geometry

– BladeEditor (add-in to ANSYS

DesignModeler)




blade geometry

• Define meridional flow path

• Specify blade shape

• Angle/thickness

• Vary blade shape across span,

from hub to shroud

• Produce 3D blade

ANSYS Vista TF

• Developed together with PCA

Engineers (Lincoln, UK)

– Turbomachinery design and analysis

specialists


• Simplified solution of flow in rotating

machinery

– Circumferentially-averaged equations,

with correlations for losses, incidence,

deviation

• Initial design optimization

ANSYS TurboGrid

• Automated and efficient mesh

generation for bladed

turbomachinery components

– High quality hex meshes

• Efficiently resolve boundary layers


• Flow alignment in blade passage

– Repeatable

• Minimize mesh influence in design

comparison

– Scalable

• Maintain quality with mesh

refinement

ANSYS CFD-Post

• Powerful general post-processing

• Dedicated turbo post-processing

– Turbo plots

• Blade-to-blade

• Meridional


• Meridional

– Turbo charts

• Blade loading

• Hub to shroud

• 5

– Turbo report templates

• 1 component � multi-stage

• Special macros for new transient methods

Challenge

Scale model testing is time consuming, expensive, and can be

unreliable due to scaling effects. The physics of the processes

involved are complex, involving transient, transitionally turbulent,

multiphase flow with a free surface.

Solution

Hydrodynamics & Aerodynamics

Cost-effective ship hull design


ANSYS CFD products offers reliable multiphase flow models

which allow prediction of free surface shape, forces and effects

due to cavitation. Simulation results have been validated against

towing-tank experiments and have been found to show excellent

agreement.

Benefits

CFD simulation allows the investigation of more design

alternatives, while reducing the need for expensive towing tank

tests. ANSYS CFD allows for rapid completion of what-if

scenarios providing valuable insight into design variations such

as appendage placement. The end result is hulls which perform

better in all key areas.

The following example presents application of the coupled

solution technique in the ANSYS CFD software to free surface

type problems. The resulting methodology gave good

agreement with the available experimental results for a

canonical racing yacht. The presented example also

demonstrates the potential for the approach to be applied to

compute the resulting stresses in a vessel, and its dynamic

response to wave motion.


Cost-effective ship hull design


response to wave motion.Photograph of yacht hull configuration in the

towing tank.

ANSYS CFX predictions for the yacht hull, in a similar

position including its response to the motion of the

vessel and the free surface.

2 DOF Catamaran

IFS consultants used ANSYS CFD fluid dynamics software to

simulate the nose of the boat entering the water as it rides over

the crest of a wave. The consultants looked at a large number of

different designs to determine the magnitude of the resultant

forces, with the goal of generating the largest possible resultant

force pulling the nose out of the water. They also looked at

alternate designs for appendages that create a low-pressure ANSYS CFD predictions for the yacht hull, in a similar


Cost-effective hull design


alternate designs for appendages that create a low-pressure

zone underneath the hull to pull water out of the drain.ANSYS CFD predictions for the yacht hull, in a similar

position including its response to the motion of the

vessel and the free surface.

Simulation designed to evaluate stability of original

designOriginal drainage appendage Optimized drainage appendage

with bullet-shaped scupper


CFD first entered the sport of competitive swimming in a

significant way with the development of Speedo’s FASTSKIN

FSII swimsuit, developed for use at the 2004 Athens

Olympics. February 2008 saw the further development of

Speedo’s CFD program with the global launch of its LZR

RACER® suit ahead of the Beijing games. Using FLUENT

Speedo’s full-body swimsuit takes

advantage of simulation technology


RACER® suit ahead of the Beijing games. Using FLUENT

technology from ANSYS, Inc., Speedo used CFD analysis to

guide, test and refine the final design of the suit, bringing

together a range of research with the goal of improving

performance.

Flow pathlines coloured by local flow velocity around an elite

male swimmer wearing a LZR RACER suit in the glide position

For the investigation of loads on offshore structures like

oil rigs, it is essential to model the propagation of steep

breaking water waves over several wave lengths. To

check the ability of ANSYS Fluent to model extreme

wave conditions, a breaking dam problem was simulated

and compared to measurements from a wave tank.


Wave Simulations


Images show the comparison of experiment (grey) and

simulation (color) at different times following the dam

break; white regions correspond to breaking waves in

the experiment

Easy Boundary Condition Setup.

Open Wave Channel Flow Boundary

Condition and Open Channel Flow

Boundary Condition setup panels.

Four of the top teams, including BMW ORACLE Racing

from the United States, South Africa’s Team

Shosholoza, Emirates Team New Zealand (ETNZ) and

defending champion Alinghi from Switzerland, use

computational fluid dynamics (CFD) software from

ANSYS, Inc. to predict the effect of design alternatives

An upwind aerodynamic simulation of

the Team Shosholoza yacht clearly

shows the tip vortices. Induced drag

reduction is important for sails

operating near their maximum lift.

Utilisation of CFD to compute both hydrodynamic and

aerodynamic flows around the boat



ANSYS, Inc. to predict the effect of design alternatives

on yacht performance down to the smallest details.

Team Shosholoza

The two most critical aspects of yacht performance are the sail

aerodynamics and the hydrodynamics of the hull and

appendages. The art of yacht design is to extract drive force

because the two fluids (air and water) have different speeds and

directions. The curvature of the sails generates lift in a manner

Alinghi simulation

of typical downwind

sail geometry

illustrates the way

air flows over the

sails. A large vortex

is created behind

the spinnaker, a

billowing sail used

when the wind is


Utilisation of CFD to compute both

hydrodynamic and aerodynamic

flows around the boat


directions. The curvature of the sails generates lift in a manner

similar to an airplane wing, while the keel of the boat generates

lift in the opposite direction — like the opposite wing of the

airplane — to prevent the boat from moving sideways. As in

aircraft design, improving performance of a racing yacht is

basically a question of maximizing lift and minimizing drag.

Small changes in geometry often make the difference

between a competitive boat and an also-ran.

when the wind is

behind the boat.

CFD simulates the wind

flowing over the deck and

cockpit of the Alinghi boat.

Note the vortex that

formed in the bow where the

wind wraps around

on the deck.


Under the direction of Grant Simmer, the coordinator of the

Alinghi Design Team, two new boats have been designed and

constructed for the 2003 America’s Cup race. This has been the

result of a Team project, involving all twelve of Alinghi’s





result of a Team project, involving all twelve of Alinghi’s

designers, researchers from the EPFL, and many Alinghi sailors.

Match racing trials of Alinghi boats in

Auckland

A bird’s-eye view of two sailboats on the water, sailing downwind;

pathlines indicate the interaction between the boats

Comparison of computed (blue line) and experimental (red circles)

values of the waterline on the surface of a 2.5m Wigley hull

BMW ORACLE Racing ran models with

10 to 15 million cells on large computer

clusters that can resolve the

performance impact of the smallest

design changes. The team’s designers

Utilisation of CFD to compute both hydrodynamic and

aerodynamic flows around the boat



design changes. The team’s designers

simulated the performance of large

numbers of different sail shapes and

trims to understand performance under

a variety of conditions. They evaluated

the aerodynamic effects of the deck,

such as the shape of edges and corners

and the position of the winches, and

they also looked at the shape of

underwater components, such as the

ballast bulb.

Fluid-structure interaction:

deformable sail membrane

analysis




BMW ORACLE Racing ran models with 10

to 15 million cells on large computer

clusters that can resolve the performance

impact of the smallest design changes. The



impact of the smallest design changes. The

team’s designers simulated the performance

of large numbers of different sail shapes

and trims to understand performance under

a variety of conditions. They evaluated the

aerodynamic effects of the deck, such as

the shape of edges and corners and the

position of the winches, and they also

looked at the shape of underwater

components, such as the ballast bulb.

BMW ORACLE Racing has

analyzed and improved nearly

every detail of the boat,

including the keel–ballast bulb

juncture.

ANSYS Workbench

Fully parametric

►Size & shape parameterization

►Parameterize geometry

►Parameterize materials & loads

Integrated Parameter Management

►Tightly integrated with CFD apps

ANSYS Workbench for ParametricDesign Exploration & Optimization


ANSYS Workbench

►Tightly integrated with CFD apps

►Store and compare Design Points

►Review design permutations

Design Exploration & Optimization

►Multiphysics optimization

►Several optimization methods

►Create response surfaces

►Introduce parameter uncertainty

Response surface

Local sensitivity

Spider chart

HVAC (Heating, Ventilation, Air

Conditioning)

Heating and Cooling

applications

Air-cooled (ventilation) systems have been adopted

in recent years, and are gradually replacing water-

cooled systems because they offer reasonable

performance at low cost. In addition to meeting

regulations, ship owners also want to understand the

performance of the refrigeration cooling system,

since it impacts the quality of the refrigerated cargo.


Courtesy of Flensburger Schiffbau-Gesellschaft (Flensburg Shipyard)

Temperature

distribution on the

outside of NEMS

reefer containers

Courtesy of Daewoo Shipbuilding

since it impacts the quality of the refrigerated cargo.

Warm air from hot parts to electric control cabinet due to ventilation

HVAC (Heating, Ventilation, Air

Conditioning)

Improving Air Quality on

Cargo Vessels

The simulation of exhaust plumes using

ANSYS Fluent is now part of the regular

design cycle at Daewoo Shipbuilding and

Marine Engineering Co., Ltd. (DSME), for

those vessels with dubious exhaust emission

imperative troubleshooting between the launch


imperative troubleshooting between the launch

and delivery of a vessel. ANSYS Fluent CFD

solution enabled DSME to have a quick and

economical way of keeping its vessels

immaculate, while avoiding time-consuming

and costly tests to improve their performance.

Exhaust plumes from the original design engulfed the rear of the ship.

Exhaust plumes from the modified design are carried away from the ship.

Courtesy of Daewoo Shipbuilding

The FSI solution from ANSYS is an integrated part of

its multiphysics technology, in which the ANSYS Multi-

field solver is used to create a true bi-directional FSI

capability for time-transient or steady-state analysis

with moving or deforming geometry. The structural

part of the analysis is solved using the well-

Importance of Fluid Structure

Interaction (FSI)

Multiphysics


part of the analysis is solved using the well-

established full-capability ANSYS structural

mechanics and fluid mechanics solvers. The solutions

can run simultaneously on the same or different

machines, thus accommodating larger models more

efficiently than a multi-field solver using a single

machine environment.

Hydrodynamic analysis with a given sea state provides

motion profile for CFD and FEA. Velocity motion

profiles applied using Six Degree Of Freedom model in

CFD solver accelerations could be applied directly to

momentum equations. Volume of Fluid model used to

model gas-liquid interface in CFD solver. Transient one-

Storage Vessel Design

Effects of FPSO Movement

Multiphysics


model gas-liquid interface in CFD solver. Transient one-

way FSI, surface pressures mapped from CFD analysis

to FEA model. Displacement profiles from

Hydrodynamic solver applied to FEA model to account

for inertia of solid structure.

Deformations resulting from fixing the tank ‘feet’ and applying

only the pressure profile from the CFD calculationVon-Mises stresses on internal baffles resulting from fixing the

tank ‘feet’ and applying only the pressure profile from the CFD

calculation.

Renewable Energy

Challenges

• Aerodynamic efficiency across expected wind speeds and wind profiles

Benefits

• Virtual prototyping of initial candidate designs for reduced wind tunnel and full

• Turbine Sitting

• Blade Design

Wind Energy


speeds and wind profiles

• Determining integrity of structures made of complex composite materials

• Minimizing noise

• Maximizing strength while minimizing weight

• Maximizing efficiency of turbines and turbine placement

• Steep terrain

• The impact of turbine-turbine shadow effects for varying wind directions and speeds

• Prediction of power output

designs for reduced wind tunnel and full scale testing

• Automation of design of experiments/wind conditions of interest

• Lower design costs

• Optimize turbine output and placement

• Wind speed prediction over complex terrain

• Upfront prediction of power output as a function of wind speed and direction

Renewable Energy

Engineers use structural and hydrodynamic analysis to

ensure that wave-powered electrical generation machines

produce maximum energy output and operate effectively

for decades.

“It is estimated that if just 0.2 percent of the ocean’s

untapped energy could be harnessed, it could provide

power sufficient for the entire world”

Ocean Wave


The Ocean Treader (top) is moored to an anchor while the Wave

Treader (bottom) mounts on the base of offshore structures such

as wind turbines or tidal turbines.

power sufficient for the entire world”

Dr. von Jouanne, OSU

• Point Absorbers

• Integrator/Attenuator Systems

• Oscillating Water Columns

• Extensively studied by CFD

• Wells Turbine - It should be noted that

CFD predictions of Wells turbine performance

are comparable to measured data until the

turbine stalls, after which they diverge.

Renewable Energy

Ocean Current/Tidal


• Impulse Turbines

• Cycloidal Turbines

• Kaplan / Pelton

• All with good results

• Now cavitation / erosion models

now available

Tools for Automated Solution

WindModeller

• Objective

– From Map to Mesh to CFD

to Report

– Data Extraction and

Automation of Analysis


CFD solution + automated post-processing

Windmodeller: Simulation Process

• Wind farm simulation process from user perspective

– Set up analysis on desktop computer (either via GUI or command line)

– Submit job to:

• Run possible large number of cases on the local machine or on a remote server

• Postprocess results to automatically generate reports/summary data files

– Possibility to perform additional post-processing on individual results files

using CFD Post


using CFD Post

Setup on desktopRun on local or

remote computer Report as html file

the role of simulation in marine and renewable applications · 2011-01-21 · the role of...

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