  The dynamics of frontal and transverse shocks in gaseous detonation waves is
a complex phenomenon bringing many difficulties to both numerical and
experimental research. Advanced laser-optical visualization of detonation
structure may provide certain information of its reactive front, but the
corresponding lead shock needs to be reconstructed building the complete flow
field. Using the Multi-Layer Perceptron (MLP) approach, we propose in this
study a shock front reconstruction method which can predict evolution of the
lead shock wavefront from the state of the reactive front. The method is
verified through the numerical results of one- and two-dimensional unstable
detonations based on the reactive Euler equations with a one-step irreversible
chemical reaction model. Results show that the accuracy of the proposed method
depends on the activation energy of the reactive mixture, which influences
prominently the cellular detonation instability and hence, the distortion of
the lead shock surface. To select the input variables for training and evaluate
their influence on the effectiveness of the proposed method, five groups, one
with six variables and the other with four variables, are tested and analyzed
in the MLP model. The trained MLP is tested in the cases with different
activation energies, demonstrates the inspiring generalization capability. This
paper offers a universal framework for predicting detonation frontal evolution
and provides a novel way to interpret numerical and experimental results of
detonation waves.
