for (my $i = 0; $i< scalar @files; $i++) {

    open FILE,"<",$files[$i];

    my $hashname = "wow".$i;



    while(<FILE>){

        chomp;

        my @row = split(/\t/,$_);



        push @{${$hashname}{$row[1]}}, "sth"; #really wanted is push @{$wow1{$row[1]}},"sth"  if hash used is "%wow1" when $i==1

    }

    close FILE;

}