Milovan Perić CD-adapco. Use of STAR-CCM+ in Marine and Offshore Engineering and Future Trends

Transcription

1 Milovan Perić CD-adapco Use of STAR-CCM+ in Marine and Offshore Engineering and Future Trends

2 Introduction CD-adapco is developing simulation capabilities in STAR-CCM+ specifically for marine and offshore applications: Wave models Motion models Fluid-structure interaction, etc This is happening in collaboration with software users in industry, research institutions and classification societies. The aim of this presentation is to show: Examples of application of STAR-CCM+ in marine and offshore engineering by our customers, Trends for future development in this field.

3 Example 1: Korean Shipyards, I All major shipyards in Korea use STAR-CCM+. One of the main topics is the automation of the simulation process: With previous tools, customers were able to generate 2 meshes per day; With automated STAR-CCM+ process, they can prepare15 simulations per day (few minutes for Excel data entry, 20 min. mesh generation) The automation is based on Java macros and Excel sheets. Two templates (developed by CD-adapco Korea) are typically used: High Froude number (container ships) Low Froude number (tankers) Advantages of automation: Faster process; Results less dependent on the user (probability for errors reduced). Best practices captured optimal results with minimum effort!

4 Example 1: Korean Shipyards, II Automatic refinement for free surface Automatic refinement for hull vicinity Automatic refinement for generated waves Automatic refinement for geometry details

5 Example 2: Self-Propulsion Test, I Study by CD-adapco Korea: KRISO container ship + rotating propeller, prediction of self-propulsion point Trimmed grid around hull, with local refinements Polyhedral grid around propeller, sliding cylindrical interface

6 Example 2: Self-Propulsion Test, II Comparison of measured (left, B/W) and predicted (right, color) streamwise velocity contours in the plane x/l PP =

7 Example 2: Self-Propulsion Test, III Comparison of measured and predicted resistance, thrust and torque: a reasonably good agreement is obtained

8 Example 3: Virtual Towing Tank, I A validation study at Brodarski Institut, Zagreb, Croatia

9 Example 3: Virtual Towing Tank, II A very good agreement between experiment and simulation is obtained. Such studies were performed for other hulls as well, with a similar success.

10 Example 4: Scale Effects At Brodarski Institut, scale effects for poddrives were investigated by comparing simulations at model and full scale. Model scale simulations are validated against experimental data.

11 Example 5: Lifeboat Water Entry, I Analysis by An analysis of collapse of air bubble on aft bulkhead of lifeboats was performed; the results were very close to full-scale tests (3-4%) for two drop heights. Air compressibility was very important H = 33 m H = 43 m

12 Example 6: Oil Collector, I The objective of this project was to find out how much oil is collected and goes through the pump in the original design, and then to optimize the design with respect to collecting capability. Simulation by for

13 Example 6: Oil Collector, II The final design that was built and used has been substantially modified relative to the original design based on simulation results. The collection efficiency has been substantially improved through simulation

14 Example 7: Wave Impact, I Simulation of wave impact onto a platform in shallow water by DNV (will be presented at OMAEconference 2012).

15 Example 7: Wave Impact, II Evidence of damage on a platform after it was hit by a hurricane Deformation in a simulation: good agreement with field observation Wave impact on an oil platform: Coupled simulation of flow using STAR-CCM+ and deformation of platform structure using ABAQUS. Simulation by CD-adapco Engineering Services for Chevron.

16 Example 8: Ballast Water Handling Problems with ballast water: Sediment (reduces payload, restricts water flow and delays de-ballasting, leads to increased fuel consumption due to extra weight) High cost if de-ballasting cannot be completed during time slot at terminal (less cargo can be loaded, vessel blacklisted at terminal ) Simulations performed by Germanischer Lloyd

17 Example 9: Gas Dispersion due to Leakage, I Leakage assumed to be a small opening in the wall of a high-pressure gas container. Expansion to atmospheric pressure results in a high Mach number jet flow, forming a barrel shock and Mach disk Konturplot von Machzahl- (links) und Temperatur- (rechts) verteilungen für Naturgas Leckströmung durch eine runde Lecköffnung in einer 30 Bar-Rohr Simulations performed by Germanischer Lloyd

18 Example 9: Gas Dispersion due to Leakage, II Objective: Assessment of risk resulting from natural gas leakage in a closed space housing a compressor and a turbine. The aim was to determine areas with dangerous accumulation of air-gas mixture Low Velocity Areas Areas above 50% LEL Areas above 100% LEL Hot Surfaces Cold Surfaces

19 Example 10: Roll Damping Research Project Best Roll Damping University of Duisburg/Essen TU Hamburg- Harburg Modern ship hulls form with different bilge keels 3 years research project to reduce roll motion Simulations performed by two universities and Germanischer Lloyd using STAR-CCM+ Experiments by SVA Potsdam

20 Example 11: Erosion by Cavitation, I Water flow at 35 m/s 3 angle of attack 75 hours duration of experiment Simulation (DES) over several periods of shedding Evaluation of Erosive Potential Good agreement with experiment Simulation Experiment Simulation by

21 Example 11: Erosion by Cavitation, II Damage to rudder due to erosion CFD prediction based on two fixed rudder positions (±4 deg). One needs to perform simulations at different operating conditions to produce an estimate of cavitation erosion probability Simulation by

22 Example 12: Ship-Ice Interaction Analysis of interaction between ice pieces and structures using DEM in STAR-CCM+ and co-simulation with ABAQUS Objective: Assessment of risk of damage caused by impact of ice pieces on sensitive parts of structure (like propeller blades, rudder etc.).

23 Example 13: Ship Launching Analysis of side-launching: - Load on structure - Ship motion Simulation by

24 Other Applications Exhaust dispertion Fire simulation Simulation of lowering of subsea equipment (which wave conditions are allowable) Simulation of installation of offshore equipment (wind turbines, jack-up platforms etc.) Vortex-induced motion Simulation of drill ship stability (how to increase the operating window) Optimization of vessel shape (coupled with FriendshipFramework) Wake assessment Shaft bending moments Wind drag Wave-added resistance etc.

25 Recently Released New Features Superposition of motions Overset grids Multi-component VOF with phase change at free surface

26 Future Developments Several new features which were requested by users will be implemented in STAR-CCM+ and become available in future releases: Additional motion models (prescribed motion and additional DOF) Beam models for simplified treatment of ship deformation in FSI Automatic set-up of standard virtual tests (PMM, zig-zag, circle ) Automatic local mesh refinement and coarsening (controlled by overset grid motion or flow features) Hydro-acoustics and vibro-acoustics Coupling to potential flow models for wave propagation over long distance and many other improvements in collaboration with customers and research institutions.