Barry, 18, began his career at West Brom and spent six months at Barcelona's La Masia academy.
The England under-18 international has played one senior game for Villa.
He can also play on the wing, and was a member of the Villa team that won the FA Youth Cup in May.
Aluko joins the Tractor Boys having also spent time on trial at Derby, for whom he featured in a pre-season friendly against Manchester United.
"I'm really looking forward to being a part of this project. I'm very excited," Aluko told the club website.
"I've been fortunate enough to get promoted with other teams in my career, and I want to contribute to this team now."
Meanwhile, boss Paul Cook added on Barry's arrival: "Louie is such an exciting player. He really wants to do well in a first-team environment."
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