Post by Malte Höltken

Extending Wagner's Water Impact Theory for Modern Seaplane Design Predicting water impact loads remains one of the core tasks of amphibious aircraft structural design. Among the foundational models around von Kármáns virtual mass formulation and their adaptations, Herbert Wagner's 1932 formulation stands out for introducing an unsteady potential flow solution to describe symmetric water impacts. Wagner’s time-dependent velocity potential Φ(x,t) captures the build-up of hydrodynamic pressure as a rigid wedge enters the water, with the pressure field given by p(x,t)=−ρ(∂Φ/​∂t+1/2​(∂Φ/∂x​)²) However, Wagner's methodology was developed primarily for analyzing existing designs. Engineers could verify load predictions for given hull geometries, but the theory provided limited guidance for systematic design methodology. The inverse problem—designing hull shapes to achieve specific load characteristics—remained largely empirical. More importantly, Wagner never considered structural elastic tailoring as a design parameter. This wasn't a theoretical limitation but reflected the materials of his era. Aluminum and steel seaplane construction in the 1930s allowed elastic design only within narrow bounds. Where elasticity was studied, mainly in float struts, it was treated as isolated components, not integrated hull optimization. Modern composite materials and modern computational possibilities change this fundamentally. Carbon fiber construction enables hull structures where stiffness distribution becomes a design variable. The same potential flow physics that Wagner described can now inform structural optimization beyond simple load prediction. My current research explores extending Wagner's potential flow analysis into this domain: using water impact physics to guide elastic tailoring of composite hull structures. Rather than treating loads as fixed constraints, we can design hull geometries and stiffness distributions that actively manage impact loads through controlled structural response. This represents a methodical extension of Wagner's work from pure analysis toward integrated design optimization. The goal is developing systematic approaches that combine fundamental flow physics with modern materials capabilities. The growing interest in sustainable aviation and urban air mobility applications makes this capability increasingly relevant for next-generation seaplane development, where structural efficiency and certification requirements demand more precise design methodologies. #Seaplane #Hydroaviation #StructuralEngineering #PotentialTheory #WaterImpact #AerospaceEngineering #Wagner #CompositeStructures #ElasticTailoring #StructuralOptimization #SustainableAviation #UrbanAirMobility