Experimental Study of Production Risers in Steady Uniform Flow

Abstract

Results from an experimental investigation on sectional models of multitube risers are presented. A single cylinder was tested as a reference case. The data outlined herein contain new information about the hydrodynamic behavior of various riser bundles exposed to a steady current. The bulk of the experimental data are pertinent to the measured steady drag coefficients, and the transverse and in‐line motions of such risers. Data are also provided about the influence of turbulence, surface roughness, and the separation distance between the center and satellite pipes on the loading and response characteristics of the specific riser geometries tested. It was found that when flexibility in the transverse and in‐line directions of the test cylinders is allowed, large increases in both the steady drag coefficients and response amplitudes may occur compared to fixed cylinders. These increases were seen with varying intensity in both the subcritical and critical flow regimes.