Investigation on drag reduction on rotating blade surfaces with microtextures

• Qinsong Zhu,
• Chen Zhang,
• Fuhang Yu and
• Yan Xu

Beilstein J. Nanotechnol. 2024, 15, 833–853, doi:10.3762/bjnano.15.70

• of 0.3 mm, and a spacing of 0.2 mm exhibited the best drag reduction, reducing the energy loss coefficient and drag by 1.45% and 1.31% for a single blade, respectively. Finally, the blades with the optimal microtexture parameters were tested in the wind tunnel. The experimental results showed that

• and outward dimple-like structures on the upper surface of a NACA 4415 airfoil. The results from wind tunnel experiments showed that the dimples on the airfoil surface delayed flow separation; the inward dimples increased lift by 16.43% and reduced drag by 46.66%. However, while these researches have

• conventional machining methods, thereby increasing the difficulty of verifying microtexture drag reduction. On the other hand, the cost associated with experiments required for microtexture testing, such as wind tunnel tests, is high. The present study employs numerical simulations, high precision milling, and

Biomimetics on the micro- and nanoscale – The 25th anniversary of the lotus effect

• Matthias Mail,
• Kerstin Koch,
• Thomas Speck,
• William M. Megill and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 850–856, doi:10.3762/bjnano.14.69

• the three species of beetles flying tethered in a wind tunnel. The results show that at low wind speeds, typical during insect flight, the species with the highest folding ratio and highest flapping frequencies produced the highest lift-to-drag ratio. The results are in agreement with other studies of

Micro-structures, nanomechanical properties and flight performance of three beetles with different folding ratios

• Jiyu Sun,
• Pengpeng Li,
• Yongwei Yan,
• Fa Song,
• Nuo Xu and
• Zhijun Zhang

Beilstein J. Nanotechnol. 2022, 13, 845–856, doi:10.3762/bjnano.13.75

• , microstructures and nanomechanical properties of three beetle species with different wing folding ratios living in different environments were investigated. Factors affecting their flight performance, that is, wind speed, folding ratio, aspect ratio, and flapping frequency, were examined using a wind tunnel. It

• ; flight performance; folding ratio; nanoindentation; wind tunnel; Introduction Regarding the benefits of scientific research, rescue, surveying, mapping, and many other aspects in the development of micro aerial vehicles (MAVs), miniaturization of aircraft has become a popular research topic [1]. Owing

• brevitarsis) were captured during wind tunnel tests and, based on the results, bioinspired wings and a linkage-mechanism flapping system were designed [26]. The flow behavior of live rhinoceros beetle flapping hind wings was studied by using a smoke wind tunnel and a high-speed camera [30]. Combining wind

An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

• Weili Liu,
• Hongjian Ni,
• Peng Wang and
• Yi Zhou

Beilstein J. Nanotechnol. 2020, 11, 24–40, doi:10.3762/bjnano.11.3

• obtained significant drag reduction efficiency in a wind tunnel experiment. Mariotti and co-workers [36] assessed the drag reduction performance of boat-tailed axisymmetric bodies with transverse grooves, with the consequence of significant DRRs owing to the delay of boundary layer separation. According to

Bidirectional biomimetic flow sensing with antiparallel and curved artificial hair sensors

• Claudio Abels,
• Antonio Qualtieri,
• Toni Lober,
• Alessandro Mariotti,
• Lily D. Chambers,
• Massimo De Vittorio,
• William M. Megill and
• Francesco Rizzi

Beilstein J. Nanotechnol. 2019, 10, 32–46, doi:10.3762/bjnano.10.4

• flow sensor, Wang et al. [38] performed wind tunnel tests with three different cantilever beam lengths (400 μm, 1200 μm and 2000 μm) at air flow velocities ranging between 0 and ≈45 m s−1. Progressively increasing the air flow velocity increased resistance signals approximately linearly. Average

• presented in [49]. Reynolds numbers range between Re ≈ 67 (for 10 m s−1) and Re ≈ 213 (for 32 m s−1) for air at 20 °C (kinematic viscosity ν = 15.06 × 10−6 m2 s−1) and a cantilever beam width d = 100 μm (characteristic length). This suggests steady flow conditions in the wind tunnel at the cantilever tip

• ) output range can be explained by the fact that the maximal air flow velocity of the wind tunnel (32 m s−1) did not generate enough drag force to flatten the downwind cantilever completely. In our previous work, we obtained signal saturation in air at about 40 m s−1 for a comparable but not mechanically