Drag Regime Research Articles

Studies on wave-subsea pipeline interaction

Estimation of wave induced loadings on subsea pipelines involves the evaluation of the hydrodynamic coefficients of drag, inertia, vertical inertia and lift. These coefficients vary with the methodology adopted and the order of wave theory used to compute the water particle kinematics. This paper presents a new and simple method to determine the hydrodynamic coefficients for subsea pipelines in the drag and inertial flow regime. The results are reported for three relative clearances of a pipeline model from the simulated ocean floor.

Phonon drag and the low temperature electrical resistivity of potassium

The authors present the results of a calculation of the low temperature ideal electrical resistivity of potassium which includes a consistent treatment of phonon drag. These results differ significantly from those of recent calculations which include the effect of phonon drag via the variational approach using the simplest trial functions for the electron and phonon distributions. It is shown that electron-phonon scattering does not, by itself, limit phonon drag to being a low temperature effect. Finally, it is pointed out that, as phonon drag significantly increases the relative contribution of the Umklapp process to the low temperature electrical resistivity, all recent investigations of the effect on the electrical resistivity of anisotropic relaxation of the electron distribution should be re-examined in the phonon drag regime.