The girl in the snapshot was smiling sweetly, her long hair flowing in the breeze.这里的flowing该怎么样理解。有人说是表示主动关系，用ing形式，我感觉不正确。对比The girl in the snapshot was smiling sweetly, her long hair flowed in the breeze.这里的flowed使用方法是不是正确，该怎么样理解。
her long hair flowing in the breeze是独立主格结构作随着状语，her long hair是分词短语的逻辑主语。独立主格结构做状语，分词自带逻辑主语，不依靠句子的主语。又如：
Weather permitting, we'll go outing tomorrow. 假如天气允许，大家明天去郊游。
关于目前分词构成的独立主格结构作状语，可参考以下链接：
http://www.yygrammar.com/Article/201512/4645.html
