Abstract As Computational Fluid Dynamics (CFD) and High Performance Computing (HPC) technologies matured in many other industries, the offshore industry has begun to recognize CFD-based Numerical Wave Basin (NWB) as a design tool evaluate floater more efficiently with less uncertainty than conventional ways relying on empirical methods. The recent NWB technology development focused customization of CFD software for practices validation developed analysis tools/procedures against physical...

When a ship advances at constant speed in waves, the steady flow interacts with unsteady wave field generated by ship's motion. The interaction between and appears so-called mj terms. three different models, that is, free stream, double body flow, are considered for realization of For completeness linear sense, contributions retained consistent manner expressions hydrodynamic restoring forces, which can be derived from integration linearized pressure over mean wetted part hull surface. trim...

A three-dimensional forward-speed seakeeping theory is proposed by the inclusion of a tank sloshing flow model. The methodology based on coupling model and in frequency domain. fluid forces moments due to liquid motion inside tanks are incorporated into equations vessel for coupled computations. classical expression restoring accordingly modified analysis. global responses modern LNG carrier at forward speed beam seas then calculated investigate effects between seakeeping. No prominent...

A B-spline panel method is developed to solve a boundary integral equation for three-dimensional potential flow problems. In particular, nonuniform rational (NURBS) surface introduced accommodate precise geometric description of given body. For the unknown (potential) over surface, uniform basis functions are used. collocation approach adopted numerical computations, and influence coefficients evaluated in robust manner defined by NURBS. Convergence characteristics present have been...

The appropriate radiation conditions of ship motion problem with advancing speed in frequency domain are investigated from a theoretical and practical point view. From extensive numerical experiments that have been conducted for evaluation the relevant conditions, hybrid technique is proposed which Sommerfeld condition free surface damping mixed. Based on comparison results translating pulsating Green function method, optimal factor selected, observed limitations discussed, along its...

This paper presents a methodology for identifying set of irregular sea states sloshing model test conditions that are most likely to produce large pressures on tank walls. To identify the critical states, pseudo-response amplitude operator (RAO) is defined based total wave energy sum kinetic and potential energies free surface. The mathematical formulated in frequency domain within regime flow theory. A concept intensity then introduced define severity an state area under response spectrum...

To mitigate hull excitation induced by propeller cavitation, our previous work proposed a single-nozzle air injection scheme based on the principle of acoustic destructive interference. Although inefficient energy consumption in conventional air-carpet system with multiple nozzle array could be significantly reduced method, its application was still hindered continuous usage an compressor and maintenance exposed to seawater. We, this study, take advantage properties rubber-like materials,...

A methodology for calculating the correlation factors to combine long-term dynamic stress components of ship structure from various loads in seas is presented. The proposed valid a stationary ergodic narrow-banded Gaussian process. total combined short-term sea states expressed by linear summation component stresses with corresponding combination factors. This expression proven be mathematically exact when applied single random sea. similarly appropriate considered here are due wave-induced...

Floating production, storage and offloading systems (FPSOs) have been widely used in the development of offshore oil gas fields because their many attractive features. These features include a large work area capacity, mobility (if desired), relatively low construction cost good stability. They are mostly ship shaped, either converted from existing tankers or purpose built. The hull structural scantling design for may be applicable to FPSOs; however, FPSOs own unique characteristics. located...

Due to unrestricted ocean operations of a drillship, the importance its transit speed is increasing in viewpoint reducing downtime offshore minimum. The open moonpool drillship induces additional drag when ship transit. As an unfavorable design may cause excessive drag, various ways reduce have been studied theoretical and experimental methods. In this paper, efficient way due consequently increase has proposed. reduction focused as around 30% total resistance drillship. A simple shape...

A methodology for calculating the correlation factors to combine long-term dynamic stress components of ship structure from various loads in seas is presented. The based on a theory stationary ergodic narrow-banded Gaussian process. total combined short-tem sea states expressed by linear summation component stresses with corresponding combination factors. This expression proven be mathematically exact when applied single random sea. similarly appropriate considered here are due wave-induced...

Abstract For more economic power generation, the blade size of offshore floating wind turbine becomes bigger than substructure. Consequently, structural load from to substructure under unsteady turbulent condition important for strength assessment. In conventional load-based assessment, coupling effect between hull motion and loading is ignored so that assessment based on methods has high uncertainties. Therefore, class societies recommend fully coupled time-domain analysis subsequent...