EnginSoft - Conference Abstracts

EnginSoft Users' Meeting 2007
Le Tecnologie CAE nell'Industria

Wind Analysis for ALMA Astronomical Antenna

Saluzzi A. - Thales Alenia Space
Galletti B. - Thales Alenia Space

Abstract

The Atacama Large Millimeter Array (ALMA) is an international astronomy facility. Astronomical observations will be carried out at the Array Operation Site (AOS) located at an elevation of 5000 meters above sea level on the Chajnantor plateau in the Atacama Desert in northern Chile. The array will be a synthesis radio telescope of up to 68 antennas of 12m diameter and a number of smaller antennas, operating in interferometer mode at millimeter and sub-millimeter wavelengths (0.3 to 10 millimeters).

The antennas will operate in free air during daytime and night time, as long as the atmospheric condition will remain inside the specified operating limit (atmospheric wind velocity in the range 6 - 20 m/s) and will be put in stow configuration when the atmospheric wind velocity becomes higher than 20 m/s. In addition each antenna is required to survive under pressure loads induced by a wind velocity of about 65 m/s (234 km/h).

A CFD wind analysis was performed to evaluate the environmental loads induced by atmospheric wind acting on the antenna external surfaces. The calculated static pressure distributions were provided as input data to the FEM model for assessing the impact of the atmospheric wind velocity on the Antenna Non-repeatable Pointing Error Budget. The computed heat transfer coefficients were provided as input for the overall antenna thermal mathematical model.