Why do knife have ridges?
A knife most simply has either a rectangular or wedge-shaped cross-section (saber grind vs. flat grind), but may also have indentations, whose purpose is to reduce adhesion of the food to the blade.
A serrated edge is one which has sharpened grooves and ridges all the way along the blade, which helps to cut tougher foods.
The back of the blade, at the handle end, has some grooves (called jimping), which gives the thumb a little traction during tougher cuts.
Serrations give the blade's cutting edge less contact area than a smooth blade, which increases the applied pressure at each point of contact, and the points of contact are at a sharper angle to the material being cut.
Its serrated grooves are specifically designed to cleanly slice through bread without crushing it. Bread knives can have a classic knife handle or may have an offset handle which keeps the chef's knuckles from knocking the bread while slicing.
Serrated edges are blades that have some kind of toothed or saw-like edge ground into the cutting surface. These are intended to be used much like a small saw with a back-and-forth motion. They're great for cutting through belts and ropes, fabric and various other textured materials.
The hole on the heavy-duty blade makes cutting through bone easy. The hole enables you to hold the upper part with your fingers. As you reinforce your grip on the handle, you are able to pull the blade free.
Spine - The spine is the top of the knife blade, opposite the knife edge. Bolster - The bolster is the band that joins the blade of the knife to its handle. The bolster provides balance for the knife and also helps to protect the hand from getting in the way of the knife edge.
Gravity takes care of fluids and suction is going to happen anyway. Instead, blood grooves are worked into a blade to reduce its weight without sacrificing length. This helps a knifemaker or designer achieve better balance. Blood grooves may also be used for looks, since people think they're badass.
This is mostly due to the blade's razor-sharp crests, which can slice through material without pulling at the individual fibers like a toothed blade might.
Why do some knives have wavy blades?
The waves in a flamberg blade creates vibrations which hurts the opponents hands, that doesn't sound like much but it gives you an advantage. Very useful for parrying since the enemies sword will strike, then the blade gets stuck on your wavy blade or they pull away from the impact shock.
The purpose of these scalloped-edge blades is to prevent food from tearing and produce intact slices of food. The scallops allow the blade to slide past the food without catching or bending it. This helps moist or clingy food to fall away from the blade.
The shape evolved so that the knife can efficiently perform the rocking motion used in chopping, where you bring the knife blade down to the food starting at the tip and rolling it to the heel. The tip of the knife doesn't leave the cutting board.