We present computational flow analysis of a vertical-axis wind turbine (VAWT) that has been proposed to also serve as a tsunami shelter. In addition to the three-blade rotor, the turbine has four support columns at the periphery. The columns support the turbine rotor and the shelter. Computational challenges encountered in flow analysis of wind turbines in general include accurate representation of the turbine geometry, multiscale unsteady flow, and moving-boundary flow associated with the rotor motion. The tsunami-shelter VAWT, because of its rather high geometric complexity, poses the additional challenge of reaching high accuracy in turbine-geometry representation and flow solution when the geometry is so complex. We address the challenges with a space–time (ST) computational method that integrates three special ST methods around the core, ST Variational Multiscale (ST-VMS) method, and mesh generation and improvement methods. The three special methods are the ST Slip Interface (ST-SI) method, ST Isogeometric Analysis (ST-IGA), and the ST/NURBS Mesh Update Method (STNMUM). The ST-discretization feature of the integrated method provides higher-order accuracy compared to standard discretization methods. The VMS feature addresses the computational challenges associated with the multiscale nature of the unsteady flow. The moving-mesh feature of the ST framework enables high-resolution computation near the blades. The ST-SI enables moving-mesh computation of the spinning rotor. The mesh covering the rotor spins with it, and the SI between the spinning mesh and the rest of the mesh accurately connects the two sides of the solution. The ST-IGA enables more accurate representation of the blade and other turbine geometries and increased accuracy in the flow solution. The STNMUM enables exact representation of the mesh rotation. A general-purpose NURBS mesh generation method makes it easier to deal with the complex turbine geometry. The quality of the mesh generated with this method is improved with a mesh relaxation method based on fiber-reinforced hyperelasticity and optimized zero-stress state. We present computations for the 2D and 3D cases. The computations show the effectiveness of our ST and mesh generation and relaxation methods in flow analysis of the tsunami-shelter VAWT.

中文翻译：

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海啸避难所垂直轴风力机时空变分多尺度等几何分析

我们提出了垂直轴风力涡轮机 (VAWT) 的计算流分析，该风力涡轮机也被提议用作海啸避难所。除了三叶转子外，涡轮机的外围还有四个支撑柱。柱子支撑涡轮转子和掩体。风力涡轮机流动分析中遇到的计算挑战通常包括涡轮几何形状的准确表示、多尺度不稳定流以及与转子运动相关的移动边界流。海啸避难所 VAWT 由于其相当高的几何复杂性，在几何形状如此复杂时，在涡轮几何表示和流动解决方案中达到高精度提出了额外的挑战。我们使用时空 (ST) 计算方法解决了这些挑战，该方法在核心周围集成了三种特殊的 ST 方法，ST Variational Multiscale (ST-VMS) 方法，以及网格生成和改进方法。三种特殊方法是 ST 滑动界面 (ST-SI) 方法、ST 等几何分析 (ST-IGA) 和 ST/NURBS 网格更新方法 (STNMUM)。与标准离散化方法相比，集成方法的 ST 离散化功能提供了更高阶的精度。VMS 功能解决了与不稳定流的多尺度性质相关的计算挑战。ST 框架的移动网格功能可在叶片附近进行高分辨率计算。ST-SI 能够对纺纱转子进行移动网格计算。覆盖转子的网格随之旋转，旋转网格与其余网格之间的 SI 准确地连接了溶液的两侧。ST-IGA 可以更准确地表示叶片和其他涡轮几何形状，并提高流量解决方案的准确性。STNMUM 可以精确表示网格旋转。通用的 NURBS 网格生成方法可以更轻松地处理复杂的涡轮几何结构。通过基于纤维增强超弹性和优化的零应力状态的网格松弛方法，使用这种方法生成的网格的质量得到了提高。我们介绍了 2D 和 3D 情况的计算。计算显示了我们的 ST 和网格生成和松弛方法在海啸避难所 VAWT 的流动分析中的有效性。通用的 NURBS 网格生成方法可以更轻松地处理复杂的涡轮几何结构。通过基于纤维增强超弹性和优化的零应力状态的网格松弛方法，使用这种方法生成的网格的质量得到了提高。我们介绍了 2D 和 3D 情况的计算。计算显示了我们的 ST 和网格生成和松弛方法在海啸避难所 VAWT 的流动分析中的有效性。通用的 NURBS 网格生成方法可以更轻松地处理复杂的涡轮几何形状。通过基于纤维增强超弹性和优化的零应力状态的网格松弛方法，使用这种方法生成的网格的质量得到了提高。我们介绍了 2D 和 3D 情况的计算。计算显示了我们的 ST 和网格生成和松弛方法在海啸避难所 VAWT 的流动分析中的有效性。