The optimization of the airfoil has a significant impact on the reduction of energy consumption for a rotary machine. In this paper, ANSYS Fluent is used to study the influence of different groove structure sizes on the turbulence drag of NACA0012 airfoil blades, and the drag reduction mechanism is analyzed. The results show that the groove structure can significantly reduce the drag during the working speed of the fan. The optimal groove size is s = 0.1 mm and the drag is reduced by 9.65%. The secondary vortices reduce the normal velocity gradient at the top of the groove structure, resulting in a reduction in viscous drag. However, as the groove size increases, the drag reduction effect decreases, and even the drag increases. The overall shear stress of the airfoil surface with the transverse groove structure is smaller than the original airfoil, and the velocity gradient of the airfoil surface is reduced. The two sides work together to reduce the turbulence drag of the airfoil. Besides, the spacing between the grooves increases the shear stress in some areas, but reduces the mutual interference of the vortices, so there is an optimum value for the groove spacing.

The distribution of electric vehicles (EVs) charging areas is affected by customers' behaviors, which has strong temporal and spatial characteristics. Thus, some charging stations (CSs) are always busy practically, while others are not, which leads to lower charging efficiency and profit. To solve this, a consumeroriented charging incentive strategy for EVs in multiple regions is proposed, which can guide the transfer, alleviate the congestion of CSs so as to improve the economy of scheduling. In this paper, by setting different charging prices in various regions, the pricebased transfer model (PBTM) of EVs is constructed to describe price effects on EVs' transfer behaviors. Then, the PBTM is integrated into a stochastic scheduling scheme managed by the distribution system operator (DSO). Charging income and extra cost of line loss caused by charging are additionally considered to maximize the total profit of DSO when scheduling. Finally, the applicability and economic advantages of the proposed strategy are analyzed with different CSs' capacity as well as users' price sensitivity and EVs' regulation depth, and the influence of important parameters are investigated deeply.

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.

Marine anti-pollution is a difficult issue in marine development. At present, marine anti-fouling researches mainly focus on three aspects: chemical, physical and biological. With the spread of the concept of environmental protection, the development of environmentally friendly, bio-adaptive anti-fouling technology has become a new development trend, and micro-structure surface anti-fouling technology has become a research hotspot. This paper introduces the profile and impact of biofouling, highlights the antifouling mechanism and research progress of microstructure technology, and describes the adhesion characteristics of the three main fouling organisms on the microstructure surface.

The research of marine antifouling is mainly conducted from the aspects of chemistry, physics, and biology. In the present work, the movement model of microorganisms along or against the flow direction on the microstructural surface was established. The model of globose algae with a diameter of 5 μm in the near-wall area was simulated by computational fluid dynamics (CFD), and the fluid kinematic characteristics and shear stress distribution over different-sized microstructures and in micropits were compared. Simulation results revealed that the increase of the β value (height to width ratio) was prone to cause vortexes in micropits. In addition, the closer the low-velocity region of the vortex center to the microstructural surface, the more easily the upper fluid of the microstructure slipped in the vortex flow and reduced the microbial attachment. Moreover, the shear stress in the micropit with a height and width of 2 μm was significantly higher than those in others; thus, microbes in this micropit easily fell off.