Hey, @S,
you can have a look at the below given example:
s= "reading a book is great"
print(re.findall(r'\b\w[aeiou]{2}\w\b',s))
For both upper and lowercase vowels.
print(re.findall(r'\b\w[aeiouAEIOU]{2}\w\b',s))
You could use [A-Za-z] instead of \w, if you don't want a digit or _ exists before or after the vowels. Because \w also matches _ and digits.
print(re.findall(r'\b[A-Za-z][aeiouAEIOU]{2}[A-Za-z]\b',s))
Add case-insensitive modifier (?i) or re.IGNORECASE to do a case-insensitive match.
print(re.findall(r'(?i)\b[a-z][aeiou]{2}[a-z]\b',s))