The scale of a wind turbine is getting larger with the development of wind energy recently. Therefore, the effect of the wind turbine blades deformation on its performances and lifespan has become obvious. In order to solve this research rapidly, a new elastic actuator line model (EALM) is proposed in this study, which is based on turbinesFoam in OpenFOAM (Open Source Field Operation and Manipulation, a free, open source computational fluid dynamics (CFD) software package released by the OpenFOAM Foundation, which was incorporated as a company limited by guarantee in England and Wales). The model combines the actuator line model (ALM) and a beam solver, which is used in the wind turbine blade design. The aeroelastic performances of the NREL (National Renewable Energy Laboratory) 5 MW wind turbine like power, thrust, and blade tip displacement are investigated. These results are compared with some research to prove the new model. Additionally, the influence caused by blade deflections on the aerodynamic performance is discussed. It is demonstrated that the tower shadow effect becomes more obvious and causes the power and thrust to get a bit lower and unsteady. Finally, this variety is analyzed in the wake of upstream wind turbine and it is found that the influence on the performance and wake flow field of downstream wind turbine becomes more serious.

The deformation and vibration of wind turbine blades in turbulent environment cannot be ignored; therefore, in order to better ensure the safety of wind turbine blades, the study of air-elastic response of wind turbine blades under turbulent wind is indispensable. In this paper, the NREL 5MW wind turbine blades are modeled with accurate 3D lay-up design, firstly, based on the joint simulation of commercial software STAR CCM+ and ABAQUS, the two-way fluid-solid coupling technology, the wind turbine under uniform wind condition is simulated, and the results from thrust, torque, structural deformation and force perspective and FAST are compared with good accuracy and consistency below the rated wind speed. Secondly, the aerodynamic performance, flow field distribution and structural response of turbulent winds with different turbulence strengths at 10 m/s were studied. The results show that the turbulence intensity has a greater impact on the amplitude of the wind turbine blade, and the stress distribution of the blade is more concentrated, which in turns affects the stability and safety of the wind turbine blade and is not conducive to the normal operation of the wind turbine.

In order to better simulate the actual working conditions of wind turbines more realistically, this paper adopts the two-way fluid–structure coupling method to study the NREL 5 MW wind turbine, considering the blade coupling deformation and equivalent stress and strain distribution of the blades with different internal structures under different working conditions. The results show that the maximum equivalent stress and strain distribution of the beam–structure wind turbine blade was near the leading edge of the blade. The maximum equivalent stress and strain distribution of the shell structure wind turbine blade was near the leading edge of the blade root, and the dangerous area is obvious but smaller than that of the beam-type wind turbine. The coupled deformation of a wind turbine model with a shell structure blade with a web is significantly reduced, and the equivalent stress and strain distribution of the skin is similar to that of the shell structure, but the numerical value and the maximum equivalent stress distribution area are significantly smaller. From the comparison of the three, the shell structure blade with a web is the best.

The motion of the liquid-carrying ship under waves is simultaneously affected by the external wave moment and the sloshing moment of the internal tank, which makes the motion of the ship more complicated. In order to explore the influence of tank sloshing on the ship motion response, the motion of the ship model with tanks at different wavelengths were simulated based on the CFD software. This paper is based on the finite volume method (FVM) to solve the RANS (Reynolds averaged Navier-Stokes) equation for numerical simulation, and the VOF (volume of fluid) method was used to capture the free surface. Using the VOF method, it is necessary to ensure that the mesh at the free surface is sufficiently fine. Based on the above conditions, the pitching motion and rolling motion of the liquid carrier in the head sea condition and the transverse wave condition were simulated, respectively. The results showed that the sloshing of the tank has little influence on the pitching motion but has a greater influence on the rolling motion. When the liquid loading rates were 0, 0.8, 0.9, and 0.98, the pitch angle changes of the ship under different wavelengths were basically the same. However, when the liquid loading rates were 0, 0.4, and 0.8, the roll angle of the ship varied greatly under different wavelengths. By simulating the roll free decay motion of the liquid carrier (the loading rates were 0, 0.2, 0.4, 0.6, 0.8 and 0.98), it was found that the essence of the sloshing effect of the tank is to change the amplitude of the ship’s rolling motion by changing the natural frequency of the ship’s rolling motion. The closer the incident wave frequency is to the natural frequency of the roll of the liquid carrier, the greater the roll amplitude of the ship.

The smoothed particle hydrodynamics (SPH) method has been playing a more and more important role in violent flow simulations since it is easy to deal with the large deformation and breaking flows from its Lagrangian particle characteristics. In this paper, the incompressible SPH (ISPH) method was used to simulate the liquid sloshing in a 2D tank with water jet flows. The study compares the liquid sloshing under different water jet conditions to analyze the effects of the excitation frequency and the water jet on impact pressure. The results demonstrate that the water jet flows can significantly affect the impact pressures on the wall caused by violent sloshing. The main purpose of the paper is to test the ISPH ability for this study and some useful regulars that are obtained from different numerical cases and study the effect of their practical importance.

Zheng, X.; Ma, Q.; Shao, S.; Hu, Z., and Gui, Q., 0000. An improved 2D + t incompressible smoothed particle hydrodynamics approach for high-speed vessel waves. The wave-generated resistance force is substantial for high-speed vessels. A thorough understanding of the wave pattern as well as its drag effect is important for improving vessel performance and optimal design. Owing to the existence of highly nonlinear waves and large deformations of the free surface, the mesh-free smoothed particle hydrodynamics (SPH) approach would provide a useful solution technique for such a practical problem. Based on the pioneering study on the combination of weakly compressible SPH with the two-dimensional (2D) + t (time) theory, the present paper carries out a further investigation on the complex wave patterns generated by a high-speed vessel, through coupling the 2D + t theory with an improved incompressible SPH (ISPH) solver. For the solid vessel boundary, a new treatment method of calculating the velocity and acceleration of the regenerated particles near the curved hull is proposed. In addition, a high accuracy numerical scheme based on the simplified finite difference interpolation (SFDI) approach is used to solve the pressure Poisson equation in the ISPH framework. The robustness of the proposed 2D + t ISPH model is demonstrated through the benchmark tests of water entry and practical applications to the self-designed laboratory experiment.