SBIR Phase II: A Fast Parallel Grid-Free Method for Simulating Turbulent Incompressible Flow In/Around Time-Varying Geometries

这个小企业创新研究（SBIR）第二阶段项目建立在为模拟时变几何形状中和周围的湍流不可压缩流而开发的算法基础上。 第二阶段的项目建议开发和商业化的国家的最先进的计算流体动力学（CFD）软件包利用开发的算法。 计算引擎是基于一个先进的并行，自适应快速多极（FMM）实现的三维拉格朗日涡边界元法。 湍流是占通过大涡模拟（LES）使用动态Smagorinsky亚网格尺度模型。 该方法是（1）网格自由的流体域，（2）几乎没有数值扩散，（3）固有的解决方案自适应，和（4）能够模拟非均匀非定常壁边界湍流。 在第二阶段，将为FMM开发更多的创新算法，以大幅提高其计算速度和准确性。 此外，还将采用工业界可能感兴趣的问题，对非定常非均匀流的大涡模拟模型进行严格测试。该软件是模拟和分析复杂层流-湍流现象的理想软件，包括大规模流动分离、非定常旋涡脱落、横流中的瞬态射流以及尾流-物体相互作用。 工业界感兴趣的例子是在诸如地面车辆或建筑物的非海崖型物体上的流动，在具有旋转和移动部件的数据存储单元中的流动;在内燃机中的流动;以及在诸如泵和风扇的旋转机械中和周围的流动。

This Small Business Innovation Research (SBIR) Phase II project builds on algorithms developed for simulating turbulent incompressible flows in and around time-varying geometries. The Phase II project proposes to develop and commercialize a state-of-the-art computational fluid dynamics (CFD) package utilizing the algorithms developed. The computational engine is based upon an advanced parallel, adaptive fast multipole (FMM) implementation of a 3-D Lagrangian vortex-boundary element method. Turbulence is accounted for via Large Eddy Simulation (LES) using a dynamic Smagorinsky sub-grid scale model. The method is (1) grid-free in the fluid domain, (2) virtually free of numerical diffusion, (3) inherently solution-adaptive, and (4) capable of modeling inhomogeneous unsteady wall-bounded turbulent flow. During Phase II additional innovative algorithms will be developed for FMM to substantially increase it computational speed as well as accuracy. Additionally, an LES model for unsteady inhomogeneous flows will be implemented and tested rigorously using problems of potential interest to industry.The software is ideal for simulation and analysis of complex laminar-through-turbulent flow phenomena involving massive flow separation, unsteady vortex shedding, transient jets in cross-stream, and wake-body interaction. Examples of interest to industry are flow over bluff bodies such as ground vehicles or buildings, in data storage units with rotating and moving parts; in internal combustion engines; and in and around rotating machinery such as pumps and fans.