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50ft roll-casts

Purposes

The purposes of this section are to show:

· A roll-cast starting and ending with the line on water showing the ability to simulate interaction with a water surface acting as “anchor”.

· A roll-cast starting and ending with the line on grass showing the ability to simulate interaction with a grass surface providing a “poor anchor”.

· The impact from the water and grass surfaces on line dynamics and rod dynamics respectively.

Input, casting strokes

The casting strokes for both casts are identical. The starting position is with the rod held horizontally behind the caster. The casting stroke involves angular as well as translational motions shown in the two graphs below:

Input, equipment

The equipment used is identical to the equipment used in the 50ft oh ref. cast.

Output, animation

Click on the graph below to start animation.

Comments, animation:

· The animation demonstrates the capability to simulate interaction of the line with a water surface. The axial drag on the fly line on the water surface produces what is usually referred to as an “anchoring effect” i.e., the water drag on the line reduces the horizontal motion of the line on the water surface during the casting stroke.

· The animation also demonstrates the capability to simulate interaction of the line with a grass surface. The axial force on the fly line on the grass surface is modeled using a friction coefficient of 0.2. The magnitude of the friction force is independent of the velocity magnitude and produces a “poor anchor” i.e., the reduction of the horizontal motion of the line on the grass during the casting stroke by the friction force is insufficient.

· It is noted that the rod movement during the casting stroke is nearly identical for the two casts. This is also shown in the graphs below for rod tip trajectories, rod bend and bending moment. The comparison shows that the difference in “anchor/surface” has a strong impact on the line dynamics but a very small impact on the rod dynamics.

· The final line position for the “grass simulation” is unrealistic. In reality, the line will also move in the 3^rd direction (out of the simulation plane) when landing on the grass. Except for the final line positioning, the simulation is considered realistic.

Output, graphs

The graphs below are shown for the time corresponding to the animation above. For explanations to the graphs please see the 50ft oh ref. cast.