Переход к турбулентности после местной закрутки потока в трубе при умеренных числах Рейнольдса

На основе физического эксперимента и прямого численного моделирования определены основные закономерности эволюции структуры закрученного течения в гладкой прямой трубе в диапазоне изменения числа Рейнольдса Re =240–1640. Закрутка потока выполнена при помощи лопаточного завихрителя. Проанализировано изменение степени закрутки, эволюции профилей продольной компоненты скорости потока и ее среднеквадратичных пульсаций с увеличением расстояния от завихрителя. Установлены значения числа Рейнольдса, при которых в исследуемом течении появляются признаки ламинарно-турбулентного перехода: интенсивный рост среднеквадратичных пульсаций скорости потока и появление перемежаемости в осциллограммах скорости. Выявлены и описаны физические механизмы турбулизации потока в окрестности оси трубы и ее пристеночной области.

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