How do I enter propeller performance data from a towing tank test or CFD analysis into NavCad?

Overview

NavCad's Propeller Object Data form allows entry of a custom KT-KQ-J dataset from any source towing tank open-water tests, CFD propeller simulations, or PropElements blade element predictions. This replaces the standard empirical series prediction with the measured or computed performance of the actual propeller.

Entering KT-KQ-J Data

• In the Propulsor data entry (Edit | Propulsor or the toolbar button), set the Propulsor type to Propeller.
• Set the ropeller .
• In the Propeller Object Data form, enter the J (advance coefficient), KT (thrust coefficient), and KQ (torque coefficient) values as ordered pairs across the operating J range.
• Enter propeller diameter, blade count, and any other geometric data required by the analysis.

Scale Correction Setting Critical

NavCad normally applies ITTC scale correction to convert model-scale KT-KQ data to full-scale predictions. When entering full-scale data from:

• Full-scale trials or operational measurements.
• Full-scale CFD simulations.
• Directly derived design KT-KQ from PropElements run at full scale.

...the scale correction must be set to None (or Custom with correction = 1.0). Leaving the default ITTC correction applied to full-scale data will produce incorrect results.

To set this: in the Propeller Object Data form, set the Options to Custom, then set Scale correction to None.

After Entry

Run the propulsion analysis as normal. The custom KT-KQ data is used directly in NavCad's propulsion model, hull-propulsor interaction calculations.

KTKQ export utility (Tools | | Export .

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