Measuring and Modeling of Wetted Surfaces (2.0) was presented at SPIE Defense + Commercial Sensing 2025 in Orlando, Florida, as a collaboration between Surface Optics Corporation and W.R. Davis Engineering. It builds on previous work which attempted to replicate a 2008 commercial dark navy grey paint used on the Canadian Research Vessel (CFAV Quest) for water film cooling experiments. Those results revealed that solar absorptivity (a function of the pigment size distribution) can vary markedly between different types of metallic paints offered by the same supplier.
This follow-up compares three candidate paints (Interlac 665, Interfine 979, Interthane 990) from the original supplier with the hope of identifying which of these matches the one used in the 2008 CFAV Quest experiments.
While low solar absorptive (LSA) paints are widely used to reduce ship cooling loads and thermal infrared signatures, their performance under real-world wet and cold conditions is less understood.
We expand on earlier in-situ measurements of dry, wet, and icy samples (previously done with Interlac 660) by testing all three paints using Surface Optics Corporation’s instruments, which measure the specular/diffuse hemispherical directional reflectance (250 nm to 25 μm) and the bidirectional reflectance (4 to 10 μm) to reveal distinct optical properties under different conditions.
The second part of the study introduces a new analytical model for wetted surface optical properties, incorporating both the dry sample measurements and existing water properties for integration into the ShipIR simulation tool. Because water’s optical properties change below 2.5 μm and reflectance in this range can only be measured at zero incidence, at least one sample must show moderate LSA hemispherical reflectivity here to validate the model.
The current and modified (hybrid) versions of the ShipIR wetted surface reflectance model will be compared against the optical properties measured by Surface Optics Corporation.
Access the full paper in the SPIE Digital Library.
Citation
D. A. Vaitekunas, Moses Kodur, Martin Szczesniak, “Measuring and modelling of wetted surfaces (2.0),” Proc. SPIE 13468, Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXVI, 1346809 (29 May 2025); https://doi.org/10.1117/12.3053469
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