Page 46: of Maritime Reporter Magazine (April 2017)

Offshore Report trimmed hexahedral cells. results for the forces were within 3 to 5 the second, more drastic simpli? cation, ? rst level of simpli? cation. For the sec-

In an intensive joint effort with the percent of experimental test data. Ulti- the entire platform geometry was re- ond (most extreme) level of simpli? ca-

Siemens PLM Software support team in mately, the ? rm simulated 13 headings placed by a simple box shape. tion, simulation results were within 4

France, HydrOcean found the correct pa- in all. In the largest divergence from The resulting geometries were simu- to 6 percent in average of experimental rameters that provided good mesh qual- test data, the simulation results differed lated numerically and also tested physi- results.

ity (wrapper and volume mesh) and good by 10 percent. Next, two levels of sim- cally in the wind tunnel.

numerical parameters for the simulation pli? cation were performed on the CFD Both levels of simpli? cations com- CFD Model Prep model. model and the corresponding 3D printed pared well for the wind load forces - One key interest of project funders

The ultimate goal was to prove the model to assess the impact of each sim- simulation results differed 5 to 10 per- Total and DORIS Engineering was to feasibility of bypassing the CAD clean- pli? cation on the measured wind loads cent from experimental results for the learn whether preparation of CFD mod- ing phase and use the surface wrapper and moments. ? rst level of simpli? cation, and 8 to 15 els from 3D CAD ? les could be made as instead and this was successfully dem- In the ? rst simpli? cation exercise in percent for the second level. For the mo- straightforward as the process of con- onstrated. the 3D printed model, small pipes were ment, however, it was harder to obtain verting 3D CAD ? les into STL ? les for replaced with porosity grids and com- a match, mainly for the most simpli? ed 3D printing. From extensive prior expe-

CFD Results Closely Match plex objects such as pumps and valves geometry. For the most highly detailed rience using CAD data to create physi-

Experimental Data were replaced with boxes, cylinders geometry, simulation results were within cal models for wind tunnel testing, the

Initially, HydrOcean simulated seven or other simpli? ed shapes - typical of 4 to 8 percent in average of test results. companies knew that this process - al- to eight wind heading angles, and the industry-standard practice at present. In No comparisons were made for the though requiring some simpli? cation of

FIGURE 3: Full-featured 3D printed model used in wind tunnel and wave-basin testing.

46 Maritime Reporter & Engineering News • APRIL 2017

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