Abstract:For the fuselage with the wing center section of a civil aircraft, the effects of horizontal velocity, vertical velocity, pitch angle and upswept angle upon the horizontal force, vertical force and pitch moment on the fuselage during the forced water entry process are investigated numerically. In the numerical simulation, the unsteady compressible Reynolds-averaged Navier-Stokes (RANS) equations and the realizable k-ε turbulence model are solved; the volume-of-fluid method is used to capture the water-air interface; the global moving mesh method are used to deal with the relative motion between the fuselage and the water. The results show that the vertical force coefficient and pitching moment coefficient of the fuselage are determined by the impact effect caused by vertical velocity and the flow effect caused by horizontal velocity. When the horizontal velocity increases, the horizontal flow effect increases, the horizontal force and vertical force coefficient of the fuselage reduces, and the pitch moment coefficient increases. As the vertical velocity increases, the impact effect increases, resulting in the increase of the horizontal force and vertical force coefficient of the fuselage. The effects of pitch angle and upswept angle on the horizontal force coefficient are small. The decrease of pitch angle will cause the increase of vertical force coefficient and pitch moment coefficient, because the central wing box will touch the water surface earlier. The increase of the upswept angle will lead to the increase of the impact effect, and then the increase of the vertical force coefficient and pitch moment coefficient.