Local Wind Climate Research Articles

Wind tunnel studies for the aerodynamic shape for Sydney Australia

As a component of the planning process for the future development for the Sydney CBD, wind tunnel studies were carried out on five different aerodynamic shapes. These represented three possible future development options, the present (1988) development and the 1940 development. Assessment of the local wind climate was facilitated by measurement of the mean velocity ratio which compared local wind speed with the geostrophic wind speed for wind directions of interest. This enabled evaluation of the windiness at street level from storms as well as the penetration of gentle sea breeze winds. By comparing the mean speed ratios for the strategies tested, the preferred shape was identified which maintained the largest area with mean speed ratios greater than 0.2 to ensure adequate flushing while minimising the areas exceeding ratios of 0.5. This development strategy represents an improvement in the existing wind climate and permits substantial future development.

Model studies and the prediction of full scale levels of stack gas concentration.

The scaling requirements and experimental procedures for modeling the diffusion of stack plumes during conditions of neutral atmospheric stability are presented. Wind during neutral conditions is modeled by a turbulent boundary layer developed naturally over a long fetch of upstream terrain. Both the inertia and buoyancy properties of the plume are simulated; the latter is achieved by using an air helium mixture. The helium is also used as a tracer gas for measurements of model concentrations resulting from the stack operation. Some illustrative experimental measurements are presented. The methodology developed at the Boundary Layer Wind Tunnel Laboratory for providing predictions of full scale stack gas concentrations is summarized. In this approach wind tunnel derived measurements of stack gas concentration at particular down wind locations, wind speeds, wind directions, and power plant operating conditions can be combined with the statistical description of the local wind climate to arrive at predictio...