Low Speed Research Articles

Speed dependence, sources, and directivity of small vessel underwater noise.

Small vessels (<10 m) radiate underwater noise in sensitive coastal environments, but there is insufficient knowledge of their noise radiation. Through detailed measurements of seven small boats and a jet ski in a shallow water environment on the Swedish west coast, this study presents results on the speed dependence of small vessel underwater noise, its sources, and its directivity. For vessels with planing hulls, broadband source levels increase with speed until planing is attained. When planing, source level dependence on speed is weak. A detailed noise source analysis of one vessel showed that at low speed, tonals from the engine dominate the noise radiation, whereas at higher speeds, propeller tonals and broadband noise dominate. Noise radiation into different horizontal angles shows little angle dependence, and noise levels relative to the closest point of approach show a similar pattern across all investigated vessels. Received noise levels at approximately 100 m range are not high enough to cause hearing impairment in marine animals, but fast-moving small vessels may cause behavioural reactions or stress responses across several marine animal groups.

The association between aerobic capacity and spinal curvature and mobility in young soccer players

BackgroundThere is a lot of research in terms of injuries and performance in football and nowadays aerobic capacity, spinal posture and mobility have been taken into consideration separately in terms of performance. Considering from a biomechanical perspective, we thought spinal curvature and mobility may affect aerobic performance and investigated the relationship between them. Research questionDo young soccer players' segmental spinal curvature and mobility affect their aerobic capacity and maximal exercise performance? MethodsThirty-four young league players (mean age 16.56 ±1.11 years) were evaluated pre-season. Spinal assessments in the sagittal plane with a non-invasive, computer-assisted electromechanical device and aerobic capacity assessment with a cardiopulmonary exercise-testing device were applied. The relationship between spinal postural variables with aerobic capacity was done by Pearson correlation analysis, and simple linear regression analysis was used to estimate the effect of spinal curvature and mobility on aerobic performance. ResultsVarious parameters of aerobic performance were related to spinal curvature and mobility. Maximal oxygen uptake (VO2max) and maximal heart rate (HRmax) were negatively correlated with thoracic angle (r=-0.343, p=0.047 and r=-0.344, p=0.046; respectively). Thoracic angle was also associated with tidal volume (VT) and VO2/HR (r=-0.347, p=0.044 and r=-0.348, p=0.044; respectively). Higher thoracic mobility caused to reach the anaerobic threshold (VAT) earlier (r=-0.368, p=0.032), at a lower speed (r=-0.367, p=0.033). In other segments, lumbar mobility was negatively correlated with VT at VAT (r=-0.346; p=0.045), while spinal inclination with HR at VAT (r=-0.387, p=0.024). SignificanceAlthough it is within physiological ranges, increased spinal curvature and mobility are associated with a decrease in aerobic capacity in young soccer players. Spinal curvature and mobility especially in the thoracic region may affect the aerobic performance of a soccer player. The trainers should consider spinal alignment for not only the technical and tactical but also the general performance of the soccer player.

Investigation of various winglets using computational fluid dynamics for subsonic aircraft

Abstract The tiny, upturned, or downturned extensions at the tips of an aircraft’s wings are designated as winglets. By minimizing drag and improving fuel efficiency, they are introduced to increase the aircraft’s aerodynamic efficiency. Winglets are now a day’s employed in the commercial aircraft to minimise the induced effect caused by wing tip vortices produced at low subsonic speeds. In this article, we have selected NACA 2412, from which we have created a swept back wing with a 20-degree sweep angle that has eight distinct winglet configurations. SolidWorks 2023 is used for design work, and ANSYS 19.2 is used for analysis. The analysis is carried out by changing the angle of attack (AOA) from -6 degrees to 20 degrees with an incremental step of 2 degrees. Here, we have used the k-epsilon turbulence model to capture the turbulence and 100 m/s velocity is maintained throughout the analysis. From this analysis, a potential solution of aerodynamic co-efficient (lift, drag, cl, cd and cl/cd) are being observed. Blended winglet with cant angle 35 degrees produces high lift-to-drag ratio compared with another winglet configuration. The insights gained from the study are plotted in various graphs such as cl vs alpha, cd v/s alpha and cl/cd v/s alpha and the CFD results show a considerable improvement in aircraft’s performance after using winglets. Aluminium alloy’s high strength to weight ratio, robust corrosion resistance, enhanced conductivity, and outstanding ductility qualities will make it easier for us to manufacture winglets in the future.

Less power when more is needed. Climate-related current and possible future problems of the wind energy sector in Poland.

Heat waves, combined with an increasing share of weather-dependent renewable energy sources, lead to disruptions in the operation of energy systems. This paper estimates how energy consumption in Poland changed during four heat waves (2010-2022). It also analyzes how often wind conditions may occur in the summer, that interrupt energy production by land-based wind farms. Moreover, authors are looking at future changes of climate indices responsible for increased energy consumption and possible reduction of energy production in wind farms. During the 2010 heatwave, the increase in energy consumption during the hottest days did not exceed 4%. Later summer demand increased; in 2019, it was 8% higher than during the 2015 heatwave. In 2016-2022, energy consumption at the average daily air temperature above 26°C was over 8% higher on working days than at 18°C. Recently, even in regions with favorable wind conditions, the number of summer days with low wind speed (2 ms-1) exceeds 14. For Poland, the number of days with low wind speeds will increase by about ten. Therefore, the increasing demand for energy on hot days, combined with their more frequent occurrence, may have a negative impact on the stability of the energy system in the future.

A Study on the Manufacture of CNT Composites Bipolar Plate for the Fuel Cell Using a Nanosecond Pulsed Laser

The channels of the graphite-based bipolar plate for hydrogen fuel cells were mainly manufactured through milling due to low forming elongation and processability. However, during the milling process, the machining precision is low due to tool wear and vibration, and there is a risk of breakage. Non-traditional laser processing can solve the problems of tool wear and vibration through non-contact processing. In this study, the interaction characteristics of the nanosecond pulsed laser and CNT composites were observed, and channels and bipolar plates were manufactured. The effect of scanning speed and pulse duration was observed for interaction characteristics. Defects were observed due to high thermal effects at low scanning speed and high pulse duration. Channels were created depending on parallel pitch distance [] and Number of scans (NOS). The channel was evaluated for depth, top width, bottom width, channel angle, material removal rate, and surface roughness, and significant changes were observed depending on . The chemical composition, surface resistance, and contact angle of the laser-processed channel were measured. The laser processed channel was oxidized, and the surface resistance and contact angle increased. Finally, the manufacturability of the CNT composites bipolar plate using laser was examined.

Deformation behavior of aluminum alloy rivets for aerospace applications

For many decades, solid rivets made of high-strength aluminum alloys have been used for mechanical joining of aircraft structures. For numerical modeling of riveting processes the detailed description of the deformation behavior of the rivets is of utmost importance; however, only very little reliable material data are available. Therefore, this study reviews and investigates the deformation behavior of commercial MS20426AD3-5 countersunk rivets made of aluminum alloy AA-2117-T4 as typically used in aerospace applications. The self-consistent procedure for determining the material-specific flow curve includes (i) the exact preparation of cylindrical samples, (ii) compression testing of the samples at testing speeds of 0.05 mm/s, 0.5 mm/s and 5 mm/s, and (iii) inverse numerical modeling of the testing procedure. In general, the compliance of the testing setup must be considered for obtaining reliable flow curves, especially when testing small samples. The determined flow curve of aluminum alloy AA-2117-T4 showed higher yield stress and more distinct initial strain hardening than most of the flow curves published in literature. Although the flow curve did not show any significant strain rate dependency, notable softening due to deformation-induced adiabatic heating of the compressed sample was observed at the highest testing speed. However, the fracture strain seems to be strain rate-dependent, because samples deformed at the low testing speed did not show any signs of macroscopic fracture, whereas local fracture occurred in samples deformed at the medium and high testing speeds.

Investigation of the cooling effect of wind on rooftop PV power plants

This study investigates the cooling of PV panels installed on the roof of a 5.9 MW power plant in Bursa, Turkey, under varying wind conditions. Meteorological measurements were conducted during the summer period to analyse the cooling effects. When wind speed differences were below 0.5 m/s, the cooling effect on the PV panels ranged between 2-3°C. However, when the wind speed differences approached 1 m/s, the cooling effect increased up to 7°C. At lower wind speeds, winds blowing from behind the panels provided better cooling, whereas side winds offered improved performance as wind speed increased. Due to the roof slope and the minimal gap between the panels and the roof, winds from behind were less effective, as they could not penetrate the back of the PV panels. Side winds, on the other hand, faced no difficulty in flowing over the panel surfaces but lost their cooling effect as they passed along the long rows of panels. These findings suggest that during the design phase of PV power plants, high wind speed locations should be prioritized, and optimal configurations should be implemented to ensure uniform wind access to all PV arrays.

A computational study of the deposition of firebrands between two side-by-side blocks

The deposition of firebrands between two blocks, representing neighboring simplified structures, was investigated by large-eddy simulation and Lagrangian tracking of firebrands. Fire Dynamics Simulator was modified and implemented in simulations. The computational configuration resembled the previous wind-tunnel measurement setup including two blocks and the firebrand generator apparatus, aka NIST Dragon (Suzuki and Manzello 2021). Different wind speeds and frictional coefficients between the sliding firebrands and the ground were considered. Simulations revealed several flow effects influencing the motion of firebrands on the ground, such as re-circulation flow in the wake of the dragon, a crossflow upwind of the blocks, and twin re-circulation regions on leeward and windward sides of the blocks. At lower wind speeds, firebrands were accumulated somewhere between the dragon and the blocks, consistent with observations in the previous measurements. At higher wind speeds, the firebrands tended to accumulate momentarily before the crossflow region and then accelerate through the gap between the blocks. Some accumulated in the leeward corner of the blocks. Firebrands displayed much more dispersion in the streamwise direction compared to the spanwise direction because the normal component of the Reynolds stress was greater in the streamwise direction.

On the use of fractal geometry to boost galloping-based wind energy harvesting

In this study, we introduce fractal bluff bodies to galloping energy harvesters (GEH) to improve the performance of wind energy harvesting. Three basic sectional shapes are proposed for GEH, from which four fractal bluff bodies are developed. An aero-electro-mechanical model with distributed parameters is established to elucidate the underlying mechanism. Then numerical simulations and wind tunnel tests are conducted based on a fabricated prototype. Compared with the conventional galloping energy harvester with a cuboid bluff body (GEH-CB), the GEH with a fractal bluff body (GEH-FB) owns a lower cut-in wind speed and can generate higher voltages. The galloping critical wind speed for GEH-FB is reduced by 0.4 m/s. Furthermore, the output voltage can increase by 51.97% at the wind speed of 5 m/s. Especially, compared to the GEH-CB, the GEH-FB demonstrates a great advantage in terms of power density, being approximately 164.1% higher. Three-dimensional computational fluid dynamics (3D-CFD) shows that the wake vortex area and the space between the adjacent vortices both increase, which explains the aerodynamic mechanism of a large aerodynamic force and a performance enhancement in wind galloping energy harvesting. Finally, some practical application tests exhibit the effectiveness of the proposed fractal galloping harvesters.

Experimental Study of Flame Morphology in Slope Buildings under the Influence of Aspect Ratio and Ambient Wind

Slope structures are commonly used in buildings, but such slope structures can exacerbate the rate of fire spread, complicate building fire safety and suppression, and lead to injuries, deaths, and property damage. Particularly, the thermal hazards posed by ambient wind on sloped fires remain unquantified. In this study, a propane burner was used to simulate the flame morphology behavior of a sloped building fire. 480 tests were conducted with varying aspect ratios (1∼8) of the fire source, different ambient winds (0∼3.5 m/s), and slope inclination angles (0°∼40°). Results demonstrate that the flame length initially increases and then decreases with an increment in ambient wind velocity. Moreover, with an increased aspect ratio of the fire source (length-to-width ratio), the turning point at which the flame length peaks shift to occur at a lower wind velocity threshold. The tilt angle and height of the flame change (respectively increases and decreases) significantly at lower ambient wind speeds and they tend to asymptotically approach respective constant values. as the ambient wind is further promoted. Existing physical models of flame morphology do not consider the combined effects of fire source aspect ratio, slope inclination angle, and ambient wind. A new slope entrainment restriction factor (EF) was proposed based on an analysis of the upward and leeward entrainment volumes. Using this factor, new models for flame morphology (including flame length, flame tilt angle, and flame height) were established. The accuracy and generalizability of the new flame models have been validated using substantial reference data.

Testing Interventions for Mobility through Exercise (TIME): Study protocol for a randomized trial comparing a novel, brief home-based exercise program and a standard home-based group exercise for older adults with mobility disability

One in four older adults report difficulty walking, greatly increasing the risk of future disability and death. Though exercise improves mobility, too few older adults do it. While studies show that brief exercise sessions provide most of the benefit of longer sessions and that older adults note that “time” is a critical barrier to being active, what remains unknown is whether briefer RT sessions can improve mobility as well as, or better than, longer traditional sessions, possibly due to greater adherence. We present the design of a 12-month randomized controlled trial of 700 older adults with self-reported walking difficulty. Participants will be randomly assigned, in a 2 × 2 factorial design, to one of two home-based exercise programs: 1) Standard of Care: 45-min, three-times weekly sessions or 2) Experimental: 5-min daily sessions and to one of two doses of behavior change techniques (Standard or Enhanced) as part of their exercise program. The primary outcome measure is self-reported physical function. Secondary outcome measures include objectively measured lower extremity physical performance, walking endurance, balance, walking speed, strength and physical activity as well as self-reported falls, pain, fatigue and balance. This is one of the first studies to examine the clinical outcomes of brief exercise sessions, which may lead to a new generation of exercise programs that are optimized not only for impact, but for adherence as well.

A novel transformation free nonuniform higher order compact finite difference scheme for solving incompressible flows on circular geometries

This paper presents a newly developed higher order compact scheme that is designed on a polar grid by using an implicit form of first order derivatives on nonuniform grids. These derivatives are formulated compactly and implicitly with a relationship of the coefficients in terms of the unknown variables. The proposed scheme is free from transformation technique and third order accurate in space. The objective is to solve Stokes equations and Navier–Stokes equations on curvilinear grids using the polar nature of the coordinate system. Our newly developed scheme is used to solve several problems namely, a problem having an analytical solution, Stokes flow with different orientations of the lids for the half filled annular and wedge cavity, the lid driven polar cavity flow and flow past an impulsively started circular cylinder. Our newly developed scheme is used to analyze the flow structures for the flow governed by different physical control parameters: the cavity radius ratio, the cavity angle and the ratio of the upper and lower lid speeds with rotating coaxial cylinders and Reynolds number for the impulsively started circular cylinder. The Stokes equations and the Navier–Stokes equations are efficiently solved with Dirichlet as well as Neumann boundary conditions. The efficacy and robustness of our proposed scheme are shown through its applicability in all the complex fluid flow problems.

Efficiency high-order discontinuous Galerkin method for low speeds flows with time-derivative preconditioning

A local preconditioning high-order discontinuous Galerkin (DG) method is introduced to enhance the efficiency and accuracy of the density-based approach for low-speed flows. The method is based on the time-derivative preconditioning technique typically employed in finite volume methods. Traditional approximation methods that only precondition low-order derivatives lead to incompatibility of the equations. To extend the preconditioning technique to the DG method, we employ an analytic preconditioning mass matrix derived from the DG formulation of the preconditioned Navier–Stokes equations. Modified numerical flux functions and a self-adaptive local velocity truncation parameter are employed for DG systems with preconditioning. We demonstrate the efficiency and accuracy of the preconditioned DG method using explicit and implicit schemes for steady flows and a dual-time scheme for unsteady flows. The method has been implemented and used to compute a variety of flow problems, including inviscid and laminar flows, utilizing various degrees of polynomial approximations. Computations with and without preconditioning are performed to analyze the influence of spatial discretization on the accuracy and convergence of the DG solutions at low Mach numbers. Numerical results underscore the enhanced accuracy and convergence properties of the proposed method for low-speed flows, indicating significant performance improvements over traditional methods.

Maritime Inventory Routing with Speed Optimization: A MIQCP Formulation for a Tanker Fleet Servicing FPSO Units

This paper presents a continuous-time formulation for the management of deep-sea floating production storage and offloading (FPSO) units, which process and store crude oil from nearby oil platforms while waiting for a shuttle tanker to arrive and collect it. A heterogeneous fleet of tanker vessels travelling between the FPSO units and a port refinery is available, with the optimization deciding on the number and type of vessels to use, their route and travelling speed. The goal is to achieve an environmentally friendly solution featuring vessels travelling at lower speeds to minimize fuel consumption (a quadratic function of speed), which may require renting additional shuttle tankers to maintain production. The resulting mixed-integer quadratically constrained problems (MIQCP) can be solved by GUROBI, but not to global optimality, whereas a mixed-integer linear programming (MILP) relaxation that underestimates the total operating cost can tackle moderate problem sizes (5 FPSOs and 4 shuttle tankers).

Deciphering the Kinematic Substructure of Local Dark Matter with LAMOST K Giants

Numerical simulations indicate that correlations exist between the velocity distributions of stars and dark matter (DM). We study the local DM velocity distribution based on these correlations. We select K giants from LAMOST DR8 cross-matched with Gaia DR3, which have robust measurements of velocity and metallicity, and separate them into the disk, halo substructure, and isotropic halo components in the chemodynamical space utilizing the Gaussian mixture model. The substructure component is highly radially anisotropic and possibly related to the Gaia–Enceladus–Sausage (GES) merger event, while the isotropic halo component is accreted from the earliest mergers following the Maxwell–Boltzmann distribution (standard halo model [SHM]). We find that the GES-like substructure contributes ∼85% of the local nondisk stars in the solar neighborhood, which is nearly invariant when applying different volume cuts or additional angular momentum constraints. Utilizing the metallicity–stellar mass relation and the stellar mass–halo mass relation, we find that ∼25−15+24% of local DM is in the kinematic substructure. Combined with the stellar distributions of nondisk components, we modify the heliocentric velocity distribution of local DM. It shifts to a lower speed with a sharper peak compared to the SHM and updates the detection limits of DM direct detection experiments. We discuss extensively the degeneracies present in the GMM fitting and propose that more kinematic and chemical information such as α abundance could help to break the degeneracy in the future. Our work confirms that the local DM velocity distribution deviates significantly from the SHM and needs to be properly accounted for in the DM detection experiments.

Cost benefit analysis of reducing speed limits in Athens to 30 Km/h

The objective of this research is to investigate public acceptance and socio-economic feasibility of reducing speed limit from 50 km/h to 30 km/h in certain parts of the road network of Athens, Greece. A questionnaire was developed based on the method of stated preference for various hypothetical scenarios of time, fuel consumption and the probability of road crash to investigate road user preferences towards the reduction of speed limit and identify the most important influencing factors preferences. A total of 408 respondents were asked to choose among three alternative proposals: a) Reduce the speed limit to 30 km/h throughout the urban network except on major arteries, b) Reduce the speed limit to 30 km/h throughout the urban network and c) No Reduction (do nothing). For the analysis, two binomial logistic regression models and two multinomial logistic regression models were developed. The results indicate that increase in travel time, the importance of speed in causing a crash, the number of crashes the user has been involved in, the respondent’s driving habits are the main determinants of the users’ preferences. Furthermore, a Cost Benefit Analysis (CBA) was conducted to understand the sustainability implications of the implementation of lower speed limits (i.e., 50 to 30 km/h). In terms of socio-economic impacts, the CBA considered safety-related metrics, namely the number of road casualties of all severity levels, and environmental-related metrics, namely reductions in CO2, NOx, PM levels as well as in road user surplus metrics namely travel time increase and fuel consumption reduction. Costs considered in the analysis result from increased time spent on the road. Consequently, the investment and the operational costs along with the socio-economic impact are estimated and monetized, up to the year 2030. The positive Net Present Value (NPV) and the high Internal Rate of Return (IRR), i.e. 64.5 %, obtained as well as the sensitivity analysis results, indicate the feasibility of this policy over time. Therefore, speed limit reductions are economically viable and so, should be encouraged.

Development and Implementation of Stop-and-Go Inertial Profiler Certification Procedure in California

The ride quality of a road in California is often determined by evaluating pavement smoothness using an inertial profiler (IP). Conventional IP technology, per California Test (CT) 387, requires IP operators to maintain a minimum speed of 15 mph to collect pavement-smoothness data. However, maintaining a minimum speed of 15 mph in busy urban areas or on hilly terrains can be difficult and unsafe, often requiring traffic control. Caltrans and industry have identified a new technology, the “Stop-and-Go” (SAG) IP, for collecting pavement-smoothness data at low speeds (under 15 mph) without traffic control. The previous version of CT 387 did not allow for the use of SAG IPs. To address this issue, the Pavement and Materials Partnering Committee (PMPC) evaluated SAG IP and updated CT 387. A certification procedure for SAG IP was developed, and included in CT 387, based on a series of runs using speed profiles under various braking and acceleration conditions simulating urban traffic conditions. Any SAG profiler can be certified if it meets the requirements of AASHTO R 56 and CT 387. The certification procedure was validated using qualification runs at the Caltrans certification track, along with field testing, demonstrating that SAG IPs provide similar results to conventional IPs. Based on the validation, along with the subsequent update of CT 387, the PMPC approved the implementation of SAG IPs for optional use by Caltrans and industry. These developments helped California become one of the first states to develop and implement a certification procedure for SAG IPs.

Association Between Disease Severity and Frailty in Patients with Aortic Stenosis.

Frailty is highly prevalent among patients with aortic stenosis (AS). Nonetheless, the impact of AS severity on frailty remains unclear. This study aimed to clarify the association between AS severity and frailty in this population.This retrospective study included consecutive patients with AS who were hospitalized as candidates for transcatheter aortic valve implantation (TAVI). The prevalence of frailty, N-terminal pro B-type natriuretic peptide (NT-proBNP) level, gait speed, and geriatric nutritional risk index (GNRI) were compared between patients with severe and those with very severe AS. We employed multiple logistic regression analysis to examine the association between AS severity and frailty.A total of 137 patients were included. The prevalence of frailty was not significantly different between the severe and very severe AS groups (31% versus 30%). Similarly, no significant differences between the groups were observed for gait speed and GNRI, whereas the NT-proBNP level was significantly higher in the very severe group than in the severe AS group (P < 0.01). In the multiple logistic regression analysis, AS severity was not associated with frailty; however, gait speed and GNRI showed significant association with frailty independently of age, sex, and heart failure (very severe AS: odds ratio [OR] 1.051, 95% confidence interval [CI] 0.439-2.517; low gait speed: OR 5.109, 95% CI 1.556-16.775; malnutrition: OR 2.841, 95% CI 1.145-7.049).These findings suggest that low-intensity exercise training and nutritional therapy may be necessary in addition to AS treatment for the management of frailty in this population.

Climatic Impact on the Air Pollutant Concentrations Emitted from Gas Stations in Fallujah, Al-Anbar, Western Iraq

The research investigates the influence of climatic elements like temperature, relative humidity, rainfall, evaporation, dust storms, wind direction, and speed on the air pollutant concentrations at gas stations in Fallujah city while examining their impact on humans and the environment. This was achieved by measuring concentrations of CO, NO2, and CH4, suspended particles (TSP, PM10), and Cu, and Pb. It was found that the impact increased in July compared to January, because of the influence of the measured climatic elements. Rising temperatures increase air pollutants' concentrations in the atmosphere, while winds spread them from emission sites to distant locations. Moreover, summer temperatures significantly impacted air pollutant concentrations at the study stations, particularly at Al-Rehab gas station, with the highest recorded temperatures of 48.4°C. Some gas stations also exceeded local environmental limits for TSP, PM10, CO, NO2, and Pb. The study revealed that summer temperatures with wind speeds of 2.1 m/s resulted in the highest air pollutants values, while winter temperatures with wind speeds of 1.9 m/s decreased these values. Higher temperatures increase chemical reactions and temperature inversions, leading to increased pollution concentrations and exacerbating air quality problems in the study area. Strong winds disperse pollutants, reducing concentration in the study area, while low wind speed increases concentrations and stagnation, resulting in poor air quality in the studied sites. The importance of the current study lies in evaluating pollutants in the Fallujah city, determining their causes, the extent of the impact, and contribution of natural and human sources in causing changes in air pollutant concentrations; caused by emission from the source. Moreover, the current study showed its impact on human’s health, and trying to find solutions to limit these effects or reduce their levels to ensure the safety of the environment and health.

Bend-twist adaptive control for flexible wind turbine blades: Principles and experimental validation

This study proposes a new methodology for optimizing the power curve of a wind turbine at low wind speeds. The principles of bend-twist coupling and the mechanism of energy exchange between the structure and inflow are analyzed. For the blade’s geometric nonlinearity, the virtual displacements and strain fields are described using the Green-Lagrange strain theorem, retaining third-order terms in the energy expressions. The equations of motion are derived using Hamilton’s principle. The bend-twist coupling effects and large deformations of the blade are analyzed using the Updated Lagrange method. Notably, the angle of attack for a single blade section is influenced by bend-twist deformation, causing variations in the rotor’s maximum power coefficient from its optimal value. Additionally, the projection length of the blade, influenced by centrifugal forces, also affects the bend-twist deformation. Based on these findings, an aero-elastic coupling control strategy, termed “Bend-twist Adaptive Control”, is proposed and validated through experiments. The results demonstrate that the proposed control strategy could increase annual power production by 2.3 %. These conclusions offer a promising outlook for future wind turbine blade design and power optimization.