Purpose:
To evaluate the effects of the blast wave reflections off the facial features around the eye.
Methods:
A fluid-structure interaction computational model was employed to solve flow fields and pressure loading on a human face. This solver couples a sharp-interface immersed boundary method for flow simulation with in-house finite-element based structure dynamics solver Tahoe©. We simulated the propagation of the blast wave in three dimension coordinates to obtain the transient pressure loading on the face and the eye.
Results:
High-fidelity computer simulations confirmed highly transient and non-uniform pressure loading on the eye during blast wave impact. For example, a typical blast wave loads the cornea for less than 1 millisecond, 100 times faster than the average blinking of the eye. The reflections of the blast wave from nasal bone, cheek bone and brow ridge amplified the pressure on the globe. Due to these reflections, a planar blast wave with a pressure p just before impacting the face applied a peak pressure of around 1.7p on the globe during the impact. The loading on the eye was higher near the nasal bones as compared to that near zygomatic bones. Simulations of the blasts with different oblique angles from the sagittal plane suggested a similar loading mechanism on the eye facing the blast front and the peak pressures and pressure gradients achieved on the eye were weakly dependent on the direction of the blast front.
Conclusions:
During the impact of the blast wave on the human face, the reflections of the blast wave from the nasal bone, cheek bone and brow ridge focus and increase the pressure loading on the eye.
Keywords: trauma • computational modeling