Jones Norman L, Budge Trevor J, Lemon Alan M, Zundel Alan K
Environmental Modeling Research Laboratory, Brigham Young University, Provo, UT 84602, USA.
Ground Water. 2002 Mar-Apr;40(2):194-200. doi: 10.1111/j.1745-6584.2002.tb02504.x.
Complex stratigraphy can be difficult to simulate in MODFLOW models. MODFLOW uses a structured grid that requires that each grid layer be continuous throughout the model domain. This makes it difficult to explicitly represent common features such as pinchouts and embedded seams in a MODFLOW model. In this paper, we describe a method for automatically generating MODFLOW-compatible grids from boundary-representation solid models. Solid models are data structures developed originally for computer-aided design applications that define the geometry of three-dimensional objects. Solid models can be used to represent arbitrarily complex stratigraphy. The elevations defined by the solids are then extracted from the solids in a manner that preserves the continuous-layer requirement imposed by MODFLOW. Two basic approaches are described: The first method adjusts the MODFLOW grid dimensions (layer elevations) to fit the solid model boundaries, and the second method creates a regular MODFLOW grid and adjusts the material properties to match the changes in stratigraphy. One of the main benefits of using solid models to define stratigraphy for MODFLOW models is that it provides a grid-independent definition of the layer elevations that can be used to immediately re-create the MODFLOW grid geometry after any change to the grid resolution.
复杂地层在MODFLOW模型中可能难以模拟。MODFLOW使用结构化网格，要求每个网格层在整个模型域中保持连续。这使得在MODFLOW模型中明确表示诸如尖灭和嵌入层理等常见特征变得困难。在本文中，我们描述了一种从边界表示实体模型自动生成与MODFLOW兼容网格的方法。实体模型是最初为计算机辅助设计应用开发的数据结构，用于定义三维物体的几何形状。实体模型可用于表示任意复杂的地层。然后以符合MODFLOW所要求的连续层条件的方式从实体中提取由实体定义的高程。文中描述了两种基本方法：第一种方法调整MODFLOW网格尺寸（层高程）以拟合实体模型边界，第二种方法创建规则的MODFLOW网格并调整材料属性以匹配地层变化。使用实体模型为MODFLOW模型定义地层的主要好处之一是，它提供了与网格无关的层高程定义，在网格分辨率发生任何变化后，可用于立即重新创建MODFLOW网格几何形状。
