Locomotion & Feeding Flashcards
drag reduction
- fusiform body shape
- reduction of body wave
- reduction of fin surface area
- boundary layer modifications
drag reduction: fusiform body shape
- pointed leading shape
- posterior taper
- caudal fin interrupts perfect fusiform shape
drag reduction: body wave movement
- minimize lateral movement of head to reduce drag
- increase amplitude as wave moves in posterior direction
- transfer of body musculature energy to caudal peduncle and caudal fin
drag reduction: reduction of fin surface
- area of fins increases drag
- permanent & adjustable modifications
permanent fin design modifications
- forked caudal fin
- reduced length of medial fins
adjustable design modifications
variable erection of fins
drag reduction: boundary layer modifications
- boundary layer
- thickness of boundary layer is proportional to amount of friction
boundary layer
layer of water immediately adjacent to skin causes most of friction
approaches to reducing thickness of boundary type
- smoothing it
- roughing it
mucous
slime adds to slipperiness, can reduce drag by up to 65%
microprojections
disrupt boundary layer so it cannot grow ctenii, placoid tips, golf ball
how are swimming types classified?
- amount of body devoted to swimming movements
- fins used and type of movement
anguilliform
- body and caudal fin
- lateral curvature in spine musculature that moves in a posterior direction
anguilliform start
lateral displacement of head, & then passage of this displacement along the body axis to the tail
anguilliform end
backward facing “wall” of body pushing against the water
Ostraciform
- box/puffer like
- sculling action of caudal fin
- no body waves, body remains rigid
