  A new consistent, spatially adaptive, smoothed particle hydrodynamics (SPH)
method for Fluid-Structure Interactions (FSI) is presented. The method combines
several attributes that have not been simultaneously satisfied by other SPH
methods. Specifically, it is second-order convergent; it allows for resolutions
spatially adapted with moving (translating and rotating) boundaries of
arbitrary geometries; and, it accelerates the FSI solution as the adaptive
approach leads to fewer degrees of freedom without sacrificing accuracy. The
key ingredients in the method are a consistent discretization of differential
operators, a \textit{posteriori} error estimator/distance-based criterion of
adaptivity, and a particle-shifting technique. The method is applied in
simulating six different flows or FSI problems. The new method's convergence,
accuracy, and efficiency attributes are assessed by comparing the results it
produces with analytical, finite element, and consistent SPH uniform
high-resolution solutions as well as experimental data.

Fluid Dynamics;Computational Physics