• Generic Test Case

(1)

(2)

Structure

• Introduction

– Ice Simulations using LBM – VSP Kinematics

• Rainflow-Counting Algorithm / Fatigue Analysis

• Generic Test Case

• Real Application Test Case

• Summary and Outlook

(3)

Structure

• Introduction

– Ice Simulations using LBM – VSP Kinematics

• Rainflow-Counting Algorithm / Fatigue Analysis

• Generic Test Case

• Real Application Test Case

• Summary and Outlook

(4)

Introduction

^{1 / 24}

(5)

Lattice Boltzmann Method – Mesoscopic Method

^{2 / 24}

(6)

VSP Blade Geometry and Coordinate Systems

^{3 / 24}

(7)

VSP Kinematics

^{4 / 24}

(8)

Instrumented Model Scale VSP

^{5 / 24}

(9)

Structure

• Introduction

– Ice Simulations using LBM – VSP Kinematics

• Rainflow-Counting Algorithm / Fatigue Analysis

• Generic Test Case

• Real Application Test Case

• Summary and Outlook

(10)

Data Postprocessing

^{6 / 24}

(11)

Linear Damage Accumulation / Fatigue Analysis

^{7 / 24}

• Stress-Cycle Curve rates the performance of a component

(depending on material and geometric properties, manufacturing processes etc.)

• LDA to assess the influence of a load spectrum on the durability of a component

(match e.g. DNV GL class rules proof of operational strength)

(12)

Structure

• Introduction

– Ice Simulations using LBM – VSP Kinematics

• Rainflow-Counting Algorithm / Fatigue Analysis

• Generic Test Case

• Real Application Test Case

• Summary and Outlook

(13)

Test Case Introduction

^{8 / 24}

Single and double VSP propelled hulls

analyzed in model tests and simulations

(14)

Generic Feeding Hull – Domain Discretization

^{9 / 24}

(15)

Model Test vs. Simulation Animation

^{10 / 24}

• Homogeneous ice floe inflow approaching the propulsor

• Partial Milling in model test (splitting up pre-brokes floes to [very] small pieces)

• Fairly good agreement between model test and sim. with respect to floe dynamics

(16)

HSVA Model Test Matrix and TUHH Parameter Study

^{11 / 24}

(17)

Simulations under Ice Conditions

^{12 / 24}

(18)

Open Water vs. Ice Conditions – HSVA

^{13 / 24}

• Reasonable shift in Local Drag Force

(19)

Open Water vs. Ice Conditions – TUHH

^{14 / 24}

(20)

Ice Conditions – Case No. 1 – HSVA vs. TUHH

^{15 / 24}

• Significant filter (moving average) influence

(21)

Ice Conditions – 4 TUHH Simulation Setups ( equiv. to HSVA )

^{16 / 24}

(22)

HSVA vs. TUHH summary

• HSVA

– Plausible results with regard to Milling process

• Vanishing influence of ice floe edge length

• Mass influence might exist for varying ice thickness (not tested so far)

• TUHH

– Plausible results with regard to the Rigid Body model

• Amplitudes increase whilst increasing momentum

17 / 24

(23)

Ice Conditions – TUHH Parameter Study I

^{18 / 24}

(24)

Ice Conditions – TUHH Parameter Study II

^{19 / 24}

(25)

Ice Conditions – TUHH Parameter Study III

^{20 / 24}

(26)

Structure

• Introduction

– Ice Simulations using LBM – VSP Kinematics

• Rainflow-Counting Algorithm / Fatigue Analysis

• Generic Test Case

• Real Application Test Case

• Summary and Outlook

(27)

Voith Water Tractor – HSVA Model Test

^{21 / 24}

(28)

Voith Water Tractor – TUHH Simulation

^{22 / 24}

(29)

Model Test vs. Simulation Animation

^{23 / 24}

(30)

Structure

• Introduction

– Ice Simulations using LBM – VSP Kinematics

• Rainflow-Counting Algorithm / Fatigue Analysis

• Generic Test Case

– Open Water Validation – Ice Condition Validation

• Real Application Test Case

•

(31)

Summary and Outlook

• Summary

– Implemented VSP kinematics for single and double VSP arrangement – Validated hydrodynamic signal based on RANS and model test data – Applied Rainflow-Counting algorithm

• Prepare data according to class rules (e.g. DNV GL) for the proof of operational strength

• Ongoing and future work

– Construct realistic load scenarios / spectra for the life cycle of a VSP propelled ship (prescribe open water / ice cond. ratio)

• Run further simulations of extensive paramater studies (Variables: frequency, inflow velocity, ice conditions, take icebreaking into account, etc.)

– Define S-N curve for the underlying VSP

– Accomplish LDA and assess the VSPs operational strength

24 / 24

(32)

Thank you for your attention!

(33)

Appendix

(34)

Validation Sequence

(35)

Hydrodamic Validation of decisive Quantities

(36)

Deviations between RANS and LBM result

(37)

Open Water Validation – Rainflow Analysis (Lift)

(38)

Open Water Validation – Rainflow Analysis (Drag)

(39)

Ice Conditions – Case No. 1 – HSVA vs. TUHH (Lift+Drag)

(40)