Evaluering
Preferred solution, K12 – Appendix E Aerodynamics
This document contains a summary of aerodynamic assessment of the K12 alternative for the Bjørnafjorden crossing. Aerodynamic coefficients, both static and flutter derivatives, was calculated by use of CFD. The CFD results were calibrated versus wind tunnel tests and take into account near ground effects for the low part of the bridge. For the high bridge part at zero degree angle of attack, Cd was found to be 0.68. Near ground effects increase these numbers by 20%. Traffic typically increased the drag factor with 70%. Aerodynamic coefficients is also given for cables (typically Cd=0.8), towers and columns (both typically Cd=1.5). Recommendations for wind parameter input is given and is mainly based on N400 values. For parameters not given by N400, ESDU values are used.