Succeed in predicting complicated wind behavior around the telescope enclosure in the collaborative study with Kyushu University and Environmental GIS Laboratory Co. Ltd.!

As a research collaboration with the Research Institute for Applied Mechanics (RIAM) at Kyushu University and Environmental GIS Laboratory Co. Ltd., a large-scale numerical simulation has been successfully performed to predict and visualize the complicated wind distributions around the top of Cerro Chajnantor including the telescope enclosure and the operation building.

When designing a telescope enclosure, it is important to predict wind conditions around the enclosure which affect the scientific data quality. The enclosure design of the TAO 6.5-meter telescope is currently being elaborated so that the telescope provides stable performance. This successful achievement enables us to predict the wind conditions in detail according to the form of the enclosure. The best enclosure design will be obtained after multiple simulation runs with a variety of enclosure forms.

This numerical simulation can also be applied to control the wind condition during scientific observations. Such wind control, based on the numerical prediction, will be essential to optimize opening of the ventilation windows for the scientific operation of the 6.5-meter telescope.

Research Outline

Dr. Takanori Uchida, Associate Professor at Research Institute for Applied Mechanics (RIAM), Kyushu University, has successfully performed a large-scale numerical simulation for the enclosure of the TAO 6.5-meter telescope using a suite of computational fluid dynamics (CFD) codes (RIAM-COMPACT®) on a vector super computer at RIAM.

The airflows moving around the telescope is an important factor which affects the quality of astronomical data because observations from the ground are always carried out through the atmosphere. For example, air turbulence caused by the difference in temperature between the atmosphere and the telescope degrades the astronomical image. Even though the TAO 6.5-meter telescope has the world's highest level of observation performance, it is still necessary for achieving stable and maximum performance to control the wind conditions inside the enclosure during observations, as well as to optimize the form of structures associated with the telescope. In addition, snow accretion on the structures caused by bad weather condition would prevent quick recovery to normal operation.

To address these issues/problems, we used the Geographical Information System (GIS) to reconstruct three-dimensional object models of Cerro Chajnantor, the telescope enclosure, and the operation building.

The present research has been conducted as a collaborative study "Joint Research for construction in extreme environments based on numerical wind analysis and wind tunnel experiment; Principal Investigator: Dr. Takanori Uchida" with RIAM at the Kyushu University, the University of Tokyo, National Institute of Polar Research, and Environmental GIS Laboratory Co. Ltd..

References

Research studies related to the present results was also presented at the following websites.

• Kyushu University Press Release (Japanese)
• Kyushu University RIAM Wind Engineering Section Homepage (Japanese)