As marine biofouling seriously affects the development and utilization of oceans, the antifouling technology of microstructured surface has become a research hotspot due to its green and environmentally friendly advantages. In the present research, the motion models of microorganisms on the surfaces of five rectangular micropits, in co-current and counter-current flow direction, were established. Dynamic mesh technology was used to simulate the movements of microorganisms with different radii in the near-wall area, and the fluid kinematics and shear stress distributions in different-sized micropits were compared. Furthermore, moving microorganisms were included in the three-dimensional microstructure model to achieve the real situation of biofouling. Simulation results revealed that the vortex flow velocity in the micropits increased with the increase of the inlet flow velocity and the existence of the vortex flow effectively reduced the formation of conditioning layers in the micropits. In the downstream and countercurrent directions, the average shear stresses on the wall decreased with the increase of the micropit depth and width, and the shear stress on the inner wall of the Mp1 micropit (a patterned surface arranged with cubes of 2 µm × 2 µm × 2 µm) was found to be the largest. A low shear stress region with a low flow velocity was formed around microorganisms in the process of approaching the microstructured surface. The shear stress gradient of micro-ridge steps increased with the approach of microorganisms, indicating that microridge edges had a better effect on reducing microbial attachment.

中文翻译：

---

微结构表面微生物的三维数值模拟和防污机理

随着海洋生物污损严重影响海洋的开发利用，微结构表面的防污技术因其绿色环保的优点而成为研究热点。在本研究中，建立了五个矩形微坑表面微生物在顺流和逆流方向上的运动模型。用动态网格技术模拟了不同半径的微生物在近壁区域的运动，并比较了不同大小微坑内的流体运动学和切应力分布。此外，移动的微生物被包括在三维微观结构模型中，以实现生物污染的真实情况。仿真结果表明，随着入口流速的增加，微坑中的涡流速度增加，涡流的存在有效地减少了微坑中调节层的形成。在下游和逆流方向，壁上的平均剪切应力随着微坑深度和宽度的增加而减小，而Mp1微坑（图案化的表面上排列有2 µm×2 µm的立方体的内表面）上的剪切应力×2 µm）被发现是最大的。在接近微结构化表面的过程中，在微生物周围形成了低流速的低剪切应力区域。微脊阶跃的剪切应力梯度随着微生物的进入而增加，