This is actually one of the kind of difficult things about playing Gouki. Air tatsu combos are character specific, but generally…
If you hit them two times in the air with your first tatsu, follow up with lk tatsu, then shoryu. MOV told me that you may need to use mk tatsu instead of lk tatsu if they aren’t juggled very high by your initial air tatsu, but its difficult connecting the shoryu after the mk tatsu.
If you hit them once in the air with your first tatsu, juggle on the ground with rh tatsu, and your followup after that depends how sick you are. you can sj rh tatsu, but its one of Gouki’s most difficult combos, and doesn’t work on everyone. easiest followup is just jump rh, but you can also dash in mp or fp shoryu against most characters. mp shoryu seems easier. if they are in the corner after you juggle with the rh tatsu on the ground, you dont even need to dash up for the mp shoryu to connect against most characters.
If you hit them three times in the air, I say just do fp shoryu.
Sometimes after the initial air tatsu, I might just do lp x rh tatsu on the ground so I can taunt before they get up, but thats a gamble.