Qi Dai

• Doctor of Philosophy
• Professor (Associate) at Nanjing University of Science and Technology

The water-entry cavity sealing of elliptical cylinders is systematically investigated with experimental methods, which features the inconsistent lengths of major and minor axes. By comparing with the cylinder entering water, the effects of aspect ratio and Froude number on the cavity sealing are analyzed to reveal the mechanism of sealing mode tran...

The effects of droplet evaporation on turbulence characteristics are systematically investigated in a three-dimensional spatially developing supersonic mixing layer at the convective Mach number of 1.2 via direct numerical simulation. With the point-particle approach, the fluid–droplet interactions are achieved through the two-way coupling in the E...

Target tracking based on sonar images plays a crucial role in underwater coordinated operations and strikes. In this paper, aiming to address the problem of underwater noise interference and target boundary blurring in sonar image, we propose an enhanced SiamMask network, SiamMask-RAM, for underwater target tracking. By combining hybrid attention a...

To study the ballistic characteristics of high-speed vertical impact of projectiles on wave liquid surfaces, the method of Detached-Eddy Simulation (DES) with elliptic-blending Reynolds stress model is adopted to numerically simulate the high-speed vertical water entry of projectiles under different fifth-order Stokes wave curvatures. Through exper...

The high-speed projectile moving near the sea level will significantly suffer from the effects of waves. The water entry and exit of a high-speed projectile crossing a wave are investigated by detached-eddy simulation. Three simulations with different altitudes through the wave are conducted to analyze the altitude's influence on the cavity dynamic...

To investigate the cavitation and hydrodynamic characteristics of supercavitating projectiles in the shear flow, the Mixture multiphase and Schnerr-Sauer cavitation models are employed to simulate the underwater projectiles. The inflow average velocity is 600 m/s, and the shear rates range from 0 to 7500 s ⁻¹ . In the uniform flow, the supercavity...

In order to study the cavitation and hydrodynamic characteristics of supercavitating projectile in shear flow,the Mixture multiphase model,Schnerr-Sauer cavitation model and Realizable k-ε turbulence model were used to simulate the underwater supercavitating projectile in shear flow. The inflow average velocity was 600 m/ s,and the shear rates rang...

By direct numerical simulations, the non-isothermal effects on turbulent structures and asymmetric properties are investigated in the spatially developing supersonic mixing layers with high convective Mach numbers ( M c > 0.6). Hot air is blown in the high-speed stream, and cold air is added on the low-speed side. Two non-isothermal simulations wit...

By direct numerical simulations, the non-isothermal effects on turbulence anisotropy and growth rate are investigated in the three-dimensional spatially developing supersonic mixing layers with high convective Mach numbers ( M c > 0.6). Hot air is blown in the high-speed stream, and cold air is added on the low-speed side. Two non-isothermal simula...

By direct numerical simulations, the effects of heat release on turbulence characteristics are systematically investigated in a three-dimensional spatially developing supersonic droplet-laden mixing layer with the convective Mach number of 1.2. A one-step Arrhenius global reaction mechanism is employed for the combustion of n-decane and the liquid...

The modifications of thermodynamic fluctuations by inertial particles are investigated in decaying compressible isotropic turbulence with an initial turbulent Mach number of 1.2 through direct numerical simulations. The particles interact with turbulence through two-way coupling under the Eulerian–Lagrangian point-source framework. Five simulations...

With the Eulerian–Lagrangian point-source method, the effects of dispersed particles on turbulent structures and asymmetric properties are systematically investigated in a three-dimensional spatially evolving compressible mixing layer with the convective Mach number up to 1.2. Particles interact with the mixing layer through two-way coupling, and t...

With the Eulerian–Lagrangian point-source method, turbulence modulation by dispersed particles is systematically investigated in a three-dimensional spatially evolving compressible mixing layer with the convective Mach number up to 1.2. Particles interact with the mixing layer through two-way coupling, and three simulations with different particle...

By direct numerical simulations, the particle dispersion is systematically investigated in a three-dimensional spatially developing compressible mixing layer. The convective Mach number is 1.2 and particles interact with fluid through both the one- and two-way coupling. Six simulations are conducted with different particle diameters (Stokes numbers...

To study the conditions of standing oblique detonation wave's initiation and the effects of the inflow Mach number and the wedge angle on oblique detonation waves' structure, numerical method to simulate standing oblique detonation waves was developed and two-dimensional Euler equations with the single-step reaction model were involved. The results...

In this paper, direct numerical simulations of turbulence modulation by inertial particles in decaying compressible isotropic turbulence are performed by using the Eulerian–Lagrangian point-source approach. Particles interact with turbulence through two-way coupling and the initial turbulent Mach number is 1.2. The influence of particle densities (...

In this paper, a systematic investigation of turbulence modulation by particles and its underlying physical mechanisms in decaying compressible isotropic turbulence is performed by using direct numerical simulations with the Eulerian–Lagrangian point-source approach. Particles interact with turbulence through two-way coupling and the initial turbul...

The three-dimensional structures of a cellular detonation wave interacting with different turbulent flows were investigated using a one-step irreversible Arrhenius kinetics model. High-resolution bandwidth-optimized WENO scheme of spatial discretization and total variation diminishing temporal integration are used to solve the three dimensional che...

Comparative studies of three-dimensional spatially-developing supersonic turbulent spray reactive and non-reactive flows have been conducted by direct numerical simulations. The gas-droplet flow system has been captured with the hybrid Eulerian-Lagrangian approach. High-resolution bandwidth-optimized weighted essentially non-oscillatory (WENO) sche...

Comparative studies of different inflow turbulent forcing effects on detonation front dynamics and the flow statistics are conducted through direct numerical simulations of turbulence-detonation/shock interactions. Highresolution bandwidth-optimized weighted essentially nonoscillatory scheme of spatial discretization and total variation diminishing...