This paper addresses the critical role of drag reduction technology in the evolution of road vehicle design amidst the ongoing climate crisis. With transportation accounting for a substantial portion of the EU\'s greenhouse gas emissions, the shift towards alternatively powered vehicles highlights the need for innovative solutions to extend range, reduce fuel consumption, and lower emissions. This review thoroughly outlines the literature on appendable drag reduction devices, encompassing both passive and active techniques, and their applicability across a variety of road vehicles, including light and heavy-duty transport. Methods applied to simplified bodies such as the Ahmed or other commonly studied generic bluff bodies are clearly distinguished from those applied to more detailed road vehicles, where results hold greater practical significance due to authentic geometry. A combination of both wind tunnel and CFD works are outlined with insights given into how advancements in both computing power and CFD will greatly enhance the future outputs of drag reduction research for road vehicles. Finally, an outlook is provided on the future of the technology and how increased consumer demand for configurable vehicles will encourage increased engagement between drag reduction device manufacturers and automakers to improve the device mounting process.

BACKGROUND: Sulcus Vocalis (SV) is a voice disorder characterized by the parallel invagination of the vocal fold epithelium that adheres to the vocal ligament. This condition disrupts the vibratory function, leading to glottal incompetence, hoarseness, and vocal impairment. Despite various proposed surgical techniques, a standardized treatment approach remains elusive.
METHODS: We conducted a comprehensive search across PubMed/Medline, Embase, Web of Science, Scholar, and the Cochrane Library for studies on SV treatment. The inclusion criteria comprised original studies comparing pre- and post-treatment vocal outcomes in SV patients, published in English. We excluded case reports, reviews, studies without continuous data, and patients with vocal scar/atrophy.
RESULTS: Fifteen observational studies were included (361 patients, 53.73 % male, average age 41.64 years). 80 % of these studies employed self-reported outcomes, while 81.25 % analyzed acoustic/aerodynamic data. The follow-up period varied from 4 to 44 months. All techniques significantly improved Voice Handicap Index (VHI) scores (p < 0.001). Dissective and combined techniques exhibited greater reductions in VHI-30/10 (p < 0.001). Maximum Phonation Time (MPT) improved significantly across all techniques (p < 0.001), with dissective techniques demonstrating superior MPT outcomes (p < 0.001). Jitter improved significantly for dissective and injective techniques (p < 0.001), as did Shimmer for all techniques (p < 0.001). Notably, combined techniques displayed the most significant reductions (p < 0.001).
CONCLUSIONS: Surgical treatments significantly improve subjective, aerodynamic, and acoustic outcomes in SV patients. Dissective and combined dissective/injective techniques appear to yield better perceptual and phonatory outcomes compared to injective techniques alone. Further research is necessary to establish the optimal treatment approach for SV.

In many modern engineering fields, computational fluid dynamics (CFD) has been adopted as a methodology to solve complex problems. CFD is becoming a key component in developing updated designs and optimization through computational simulations, resulting in lower operating costs and enhanced efficiency. Even though the biomimetics application is complex in adapting nature to inspire new capabilities for exciting future technologies, the recent CFD in biomimetics is more accessible and practicable due to the availability of high-performance hardware and software with advances in computer sciences. Many simulations and experimental results have been used to study the analyses in biomimetics applications, particularly those related to aerospace engineering. There are numerous examples of biomimetic successes that involve making simple copies, such as the use of fins for swimming or the mastery of flying, which became possible only after the principles of aerodynamics were better understood. Therefore, this review discusses the essential methodology of CFD as a reliable tool for researchers in understanding the technology inspired by nature and an outlook for potential development through simulations. CFD plays a major role as decision support prior to undertaking a real commitment to execute any design inspired by nature and providing the direction to develop new capabilities of technologies.