05AB1E, 2828 13 bytes
žMSkþß©di®_i1ì}.γžMÃ}¦J…shmìžNSÛ©ai®…shmì Try it onlineTry it online or verify all test casesverify all test cases.
Explanation:
žMS # Push a list of vowels: ["a","e","i","o","u"] k žNSÛ # Pop and getTrim theall firstleading indicesconsonants of those vowels in the # (implicit) string (or -1 if the vowel isn't present in the # input-string) þ # Remove all those -1s ß # Push the minimum remaining index, or "" if none are left © # Store this new string in variable `®` (without popping) di ai # Pop, and if it's a (non-negative) integer: ®_i } # If `®` isany equalletters toare 0left (thus the input starts with a vowel): 1ì # Prepend a "1" in front of the (implicit) input-string .γ # Group the (potentially modified) input-string by: žMÃ # Keeping vowelscontains }¦ # After thea group-byvowel): remove the first item ® J # Join the other parts back to aPush string `®` again …shmì # # And prependPrepend "smh""shm" # (afterimplicitly whichprint it is output implicitly as result) # (implicit else) # (implicitly output the implicit input-string instead)