Wake II model for hydrodynamic forces on marine pipelines including waves and currents     

Said R. Sabag  Billy L. Edge  Iwan Soedigdo 《Ocean Engineering》2000,27(12)

The Wake II model for the determination of the hydrodynamic forces on marine pipelines is extended to include currents and waves. There are two main differences between the Wake II and the traditional model. First, in the Wake II model the velocity is modified to include the pipe's encounter with the wake flow when the velocity reverses. Second, the model uses time dependent drag and lift coefficients. The flow field is assumed to be the linear superposition of regular waves and uniform current and is treated as wave only but in two different phases. The model requires eight empirical parameters that are obtained from comparisons with field data for various Keulegan–Carpenter numbers and current to wave ratios. The effective velocity and the force predictions are compared with field data from Exxon Production Research Company and with the conventional model. The model gives satisfactory results and predicts lift forces that in shape, magnitude and phase relative to the velocity are in very close agreement with measured forces. For the horizontal forces the results are very accurate. A substantial improvement is obtained over the predictions with the conventional model. This work is applicable to the design of submarine pipelines laying on the sea bottom in water depths where waves or waves and currents contribute to the hydrodynamic forces.  相似文献   

GEochemical Reference Sample Bibliography For 1983     

Iwan ROELANDTS 《Geostandards and Geoanalytical Research》1984,8(2):207-218

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An alternative approach to the random response of bilinear hysteretic systems     

Koichiro Asano  Wilfred D. Iwan 《地震工程与结构动力学》1984,12(2):229-236

An analytical representation of the bilinear hysteretic characteristic is presented. Using this representation, the response of a single-degree-of-freedom bilinear hysteretic system subjected to non-stationary random excitation is examined by equivalent linearization. An ordinary differential equation is derived for the covariance matrix of the response. Numerical examples are presented and the accuracy of the approach is demonstrated. Extension of the approach to a wider class of hysteretic systems is discussed.  相似文献