Some Considerations on TTR Wake Interference Analysis

This study is an attempt to clarify some key issues in the top tension riser (TTR) wake interference analysis for offshore oil and gas risers. A wake model for strakes was developed from a series of test results conducted by a major operator, and analyses were done using this wake model to compare with analysis results using Blevins’ model, which is originally generated for bare pipes and has been commonly used in the industry for strakes. The effect of lift coefficient reduction factor was also studied and results are illustrated. Last, the effectiveness of removing strakes to improve interference performance was investigated, and results show that in some situation removing strakes could actually increase the total drag coefficients and drag forces.