The function replaces each vowel in the input string with the next vowel in the sequence (a -> e, e -> i, i -> o, o -> u, u -> a) in a circular way. It preserves the case of the original vowel.

[CODE]:
```python
def replace_vowels(s):
    vowels = "aeiou"
    mapping = {vowels[i]: vowels[(i + 1) % len(vowels)] for i in range(len(vowels))}
    mapping.update({vowels[i].upper(): vowels[(i + 1) % len(vowels)].upper() for i in range(len(vowels))})
    
    return ''.join(mapping[c] if c in mapping else c for c in s)
```
Let's run the function on a few more inputs to validate the description.

COMMAND: PYTHON(./temp/function.py "movie" "bEhavior" "sequoia" "antique" "Occurrence")