Literal use meaning the inside or center of a whirlpool or vortex. In everyday Japanese, 渦の中 is often plainer; 渦中 sounds more written or formal.
The small boat was caught in the whirlpool.
noun, noun which may take the genitive case particle 'no'
in the midst of a scandal; center of controversy; turmoil
Common figurative use for being caught up in, or at the center of, a scandal, controversy, quarrel, or public turmoil. Frequently appears in news phrases such as 渦中の人物 and 疑惑の渦中にある.
He is in the midst of a scandal.
The person at the center of the controversy held a press conference.
He is currently at the center of a scandal.
He is the person at the center of that incident.
She was unexpectedly swept into the midst of the scandal.
渦 is the whirlpool or swirl itself, while 渦中 refers to being inside or at the center of that whirlpool, whether literally or figuratively.
A Sino-Japanese compound of 渦, 'whirlpool' or 'vortex,' and 中, 'inside' or 'middle.' The figurative sense extends the image of being inside a swirling vortex to scandals and controversies.