Flush mounts are ideal for ceilings 7'10", or lower. So if your ceiling is 8 feet, a flush mount is not needed.
Flush mounts push 40% less air than a fan on a short downrod.
A fan with a short downrod, a 3 ½ inch or 4 ½ inch downrod, as shown in this video, is great for an 8-9 foot
ceiling. This will put your blades no lower than 7 feet off the ground.