flow of time; passage of time
Refers to the continuous, unstoppable movement of time. Often used in poetic or reflective contexts.
Time flies.
With the passage of time, the town's scenery also changed.
current of the times; trend of the times
Refers to the prevailing mood, fashion, or direction of an era. Less common than sense 1.
It's hard to go against the current of the times.
Standard kanji-kana mixed spelling.
Kana for 時 is common in casual writing.
Compound of 時 (time) + の (possessive particle) + 流れ (flow). The phrase is transparent and follows standard Japanese grammar.