RELAMINAR1ZATI0N OF DEVELOPING TURBULENT FLOW IN A 180#xB0; CURVED SQUARE CHANNEL: A STUDY BASED ON TEMPERATURE FLUCTUATION MEASUREMENTS

摘要

The stabilizing effects of centrifugal forces, for slightly heated airflow in a 180° curved square channel with nearly fully developed entry flow, are studied by temperature fluctuation measurements for Reynolds numbers in the transition range. Re = 2,000–4,500. The relaminarization process is caused by secondary flow due to centrifugal forces. This study confirms the feasibility of using a fine thermocouple (12·7μm) to study flow transition phenomena. The results are presented in both time and frequency domains.