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A three dimensional non-hydrostatic model for turbulent air flow

A finite-volume code is developed to compute the turbulent airflow over small-scale complex terrain. A pressure-correction algorithm is ·used to solve the threedimensional non-hydrostatic flow equations. The turbulent transport is simulated by the k- E: model using some modifications suitable for atmospheric boundary-layer application. | Vietnam Journal of Mechanics, NCST of Vietnam Vol. 22, 2000, No 3 (167 - 180) A THREE DIMENSIONAL NON-HYDROSTATIC MODEL FOR TURBULENT AIR FLOW DUONG NGOC HAI, NGUYEN THE 'nuc Institute of Mechanics, NCST of Vietnam ABSTRACT . A finite-volume code is developed to compute the turbulent airflow over small-scale complex terrain. A pressure-correction algorithm is ·used to solve the threedimensional non-hydrostatic flow equations . The turbulent transport is simulated by the k- E: model using some modifications suitable for atmospheric boundary-layer application. As an example, the model is used to simulate the flow-field around a cubical building. The same flow as a towing-tank experiment of USEPA was simulated using our code. These simulations show that, the model was capable of simulating recirculation zones behind the building. The results of calculation are also compared with available measurement data. 1. Introduction The determination of the turbulent wind field over complex terrain in the Atmospheric Boundary Layer has been a topic of numerous studies . Firstly, due to the mathematical difficulties involved in modeling the flow structure, the mean flow either has been assumed to be a simplified type of flow, or has been obtained by solving equations of motion with crude assumptions about turbulence [1]. Indeed, these models fail to reproduce certain important features of the complicated fl.ow structures over complex terrain, especially when the terrain slope is steep. Consequently, it is now recognized that in order to understand how irregularities of the ground surface distort the mean and turbulent structure of the incident fl.ow, it is necessary to solve the full set of fluid dynamics equations of mean properties using numerical methods. Recent increases in computer power mean that numerical prediction of flow in complex terrain is now viable. Consideration of the equations of mean properties reduces the problem of turbulence closure. The application of