tailieunhanh - Modeling Tools for Environmental Engineers and Scientists Episode 10

Tham khảo tài liệu 'modeling tools for environmental engineers and scientists episode 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 9 Modeling of Natural Environmental Systems CHAPTER PREVIEW In this chapter 12 examples of natural systems are illustrated. The selected examples include steady and unsteady state analysis using algebraic and differential equations solved by analytical trial-and-error and numerical methods. Computer implementation of the mathematical models for the above are presented. The rationale for selecting appropriate software packages for modeling the different problems and their merits and demerits are discussed. INTRODUCTION IN this chapter the modeling of several examples of natural environmental systems using the three types of software packages are demonstrated. The use of Excel TK Solver Mathcad Mathematica MATLAB Extend ithink and Simulink software packages in modeling aquatic soil and atmospheric systems under various conditions are illustrated. The development of the mathematical models in each case is outlined and the rationale for the selection of the software packages for each example their ease of use applicability and limitations are pointed out. The examples included here demonstrate how these software packages can be used to solve various mathematical calculi commonly encountered in environmental modeling. MODELING EXAMPLE LAKES IN SERIES The basic lake models discussed in Chapter 7 can be easily modified and refined in stages to simulate more complex and realistic situations. The 2002 by CRC Press LLC modeling of a sample problem from Thomann and Mueller 1987 involving two lakes in series is illustrated in this example. A constant load of a conservative substance K 0 had been applied to the first lake resulting in concentrations of mg L in that lake and mg L in the second lake. Then the load to the first lake is instantaneously removed. The goal is to develop a model to describe the temporal changes in the concentrations in the two lakes. The MB equations for the two lakes now yield the following coupled differential equations .