Virtual Marine Arsenal

Free Internet Rowing Model (FIRM) is a research code. FIRM evolved from an initial attempt at a reasonably comprehensive rowing model named “Michlet Rowing”.

In its present form the model tries to fill a need for a useful tool that lies somewhere between a full 3D model with CFD calculations of the complex flow fields, and simpler models that treat the rowers’ bodies as point masses and that use empirical approximations for the drag on the boat and rowers.

As input, FIRM requires the hull geometry, rowers’ anthropometry, rigging details and as functions of time, oar angles and gate normal forces exerted by rowers. Allowances are made for the air resistance of the crew, the above-water portion of the hull, the oars, and the riggers. The motion of the rower is simulated using a seven-body-segment model.

To estimate the hydrodynamic resistance, an extended form of Michell’s integral is used for the wave resistance component with modifications to account for water depth, hull yaw and pitch. An updated version of Grigson’s line is used for the skin friction, with modifications to include the effects of surge on the turbulent boundary layer.

Output is in the form of comma-separated files that can easily be read by spreadsheet programs.