Abstract: Two modular internal waverider inlets are designed at freestream Mach number of 4.0, whose intake and exit are fit for the forebody of the missile, in order to find out the flow characteristics at lower design points and analyze the factors which have an impact on the start ability of the internal waverider inlet. They are based on a basic flow field which has an uniform outflow and has been derived with the technology of stream tracing. Computational fluid dynamics(CFD) results show that the inlets have unique shock structures and flow characteristics at lower Mach number. Flooding position is one of the most important factors which can affect the start ability of the internal waverider inlet. The start Mach number reduces from 3.6 to 3.3 when the flooding position is changed from sides to bottom, further to 3.25 with one modular inlet. Besides, the basic flow field plays an important role in reducing the start Mach number. With the design exit Mach number fixed, the start Mach number nearly decreases by 0.1 when the turn angle increases by 2? with two modular inlets and can reduce to 3.1 with one modular inlet. With the intake turn angle fixed, the start ability of the inlet is only decided by the internal contraction ratio. The start Mach number almost reduces by 0.2 when the design exit Mach number increases by 0.2. The modular internal waverider inlet can capture nearly 99% incoming flow at different design points and shows the advantages of high flow capture ability and high total pressure recovery coefficient while the working range is enlarged.

Key words: internal waverider inlet, modular, start ability, computational fluid dynamics, flow capture