Aerodynamic Measurements Research Articles

Adjustable Phonatory PEEP to Treat Dysphonia: A Preliminary Investigation of Progressive Masked Voice Exercises (PMVE).

The Progressive Masked Voice Exercises (PMVE) with an innovative semioccluded ventilation mask fitted and adjustable positive end-expiratory pressure (PEEP) valve was evaluated. This study aimed to compare the effectiveness of the PMVE with the PEEP device and the Vocal Function Exercise (VFE) program on acoustic, auditory-perceptual, aerodynamic, and self-report measures. Twenty-five participants diagnosed with voice disorders met the criteria. Participants were randomly assigned to either the PMVE or the VFE group for a 6-week home therapy program. Pre- and post-data were analyzed with parametric and nonparametric statistics. Acoustic and aerodynamic measures showed no between-group or interaction group × time effects; however, a main effect of time was observed for all but one of the eight acoustic variables, indicating that both groups improved. Additional within-group analysis showed improvements in two of the eight variables for the PMVE program and four for the VFE program. No between-group differences were observed for the auditory-perceptual judgments using the GRBASI scale; however, the strain was improved for the VFE group. No differences in self-report measures were also seen, except for the VFE group. This study provides preliminary evidence for the PMVE therapy program. Further research is needed in large and diverse samples and clinical application is invited.

Aerodynamic Threshold Measures for Reflecting Glottal Closure in Voice Disorders.

Previous work suggested that phonation threshold pressure (PTP), phonation threshold flow (PTF), and phonation threshold power (PTW) could be effective aerodynamic measures for quantifying glottal incompetence. This study examined how these measures could reflect varying extent of incomplete glottal closure in individuals with voice disorders. Thirty individuals formally diagnosed with glottal incompetence, including 10 with hypofunctional disorders (hypo group) and 20 with hyperfunctional disorders (hyper group), and 30 individuals with normal voice (control group) participated in the study. PTP was measured indirectly by intra-oral pressure during production of bilabial stop consonant-vowel syllables, PTF was measured during the sustained vowel /a/, and PTW was obtained as the product of PTP and PTF. The extent of incomplete glottal closure was quantified by normalized glottal gap (NGG) and normalized glottal gap area (NGGA) based on image analysis of videostroboscopic recordings of sustained /i/. Significant differences in all threshold measures (p < .05) were found among three participant groups with medium-to-large effect sizes (ηp2 = .128-.220), with significantly higher values for the hypo group than the control group and no significant differences between the hyper and control groups. Receiver operating characteristic (ROC) analysis showed the highest diagnostic or classification accuracy contrasting between the hypo and control groups (area under the ROC curve = .717-.757), with the highest classification accuracy for PTW. There were significant, moderate-to-strong positive correlations with NGG and NGGA for the disorders group (Pearson's r = .4244-.6226) and the hypo group (r = .5689-.8949). These measures could be effective for identifying glottal incompetence, especially for hypofunctional disorders. PTW could be more sensitive than PTP and PTF in reflecting the extent of incomplete glottal closure, consistent with theoretical predictions. Their relative sensitivities for quantifying distinct incomplete glottal closures specific to different voice disorders should be evaluated in future studies.

Case study of a world hour record simulation in an elite cyclist: Insight into task failure.

The 'cycling hour-record' is one of the most prestigious events in cycling. However, little detailed analysis of such attempts is available. In preparation for a successful cycling hour-record attempt, an elite cyclist performed a full-hour simulation to provide insights into performance, physiological, aerodynamic and biomechanical limitations that could be identified in the preparation for a subsequent official attempt. Performance (speed, lap time, power and cadence), physiological (heart rate and estimated body temperature), aerodynamic (CDA, helmet angle, rotation and rock) and biomechanical (helmet, thigh and foot position changes) measurements were made throughout the attempt, in which an even-pacing strategy was employed where the point of task failure was defined as the lap which the rider could no longer perform at the targeted lap split (16.6s) or quicker. The cyclist did not achieve the target distance (54,000m) during the simulation. The final distance achieved for the hour was 53,250m. Task failure occurred at 38min and 33s (lap 139/34,750m) into the simulation. Notably, there was a decrease in power output, accompanied with an increase in the estimated body temperature, changes in pedalling kinematics and an increase in aerodynamic drag. The reduction in performance (leading to task failure) during a cycling hour record simulation is underpinned by a decrease in power output as well as an increase in aerodynamic drag due to biomechanical changes in the cycling technique.

Unsteady Propeller Wake Interference on Wing in Tractor Configuration at Low-Reynolds-Number Condition

This study investigates the unsteady interaction between the propeller slipstream and NACA0012 airfoil, which causes laminar separation at a moderate angle of attack and nonlinear aerodynamic characteristics at low Reynolds numbers. The Reynolds number based on chord length was set to c, and the propeller advance ratio was set to J=0.8. Wind-tunnel experiments were conducted, including aerodynamic force measurement and time-resolved particle image velocimetry visualization. Regarding time-averaged characteristics, the propeller installed condition exhibits a linear change in lift; reduced drag; and, consequently, an improved lift-to-drag ratio. Consistent with the aerodynamic characteristics, suppressed separation and reduction in wake deficit are confirmed in the time-averaged flowfields. Additionally, vortex formation and shedding synchronized with propeller rotation are observed in unsteady flowfields at the middle and high angles of attack. This periodic and large-scale vortex structure suggests the possibility of further improving the performance of the propeller–wing system in low Reynolds numbers.

Research on design method of inertial interference self-compensating balance

This paper proposes a design method for a wind tunnel balance that can compensate for inertial interference, aiming to address the issue of short effective time in pulse wind tunnels. This method also tackles the problem of the force measuring system’s inability to dampen quickly and the coupling of inertia vibration signals with the output signal of the balance, which affects aerodynamic measurement accuracy. The method calculates vibration displacement at specific positions of the balance structure using its acceleration, constructs compensation signals based on the relationship between these displacements and balance outputs, and then superimposes them onto the balance signal for compensation. The effectiveness of this compensation method is evaluated through finite element simulations and wind tunnel tests. The results demonstrate that by compensating for the balance signal, there is a significant reduction in the amplitude of the inertia vibration signal, leading to an enhancement in the repeatability accuracy of the measurement. This compensation method effectively solves under-compensation or over-compensation issues when accelerometers are placed on complex models with various modes, where obtaining accurate compensation signals becomes challenging. It provides a new technical approach to improve aerodynamic measurement accuracy by mitigating inertial interference during pulse wind tunnel testing.

Aerodynamic Measurements of Hypersonic Free-Flight via Optical Tracking and Bayesian State Estimation

Optical force and moment measurements of hypersonic free-flight can cover a range of attitudes during a single test and avoid difficulties encountered by alternative measurement techniques. However, the signal to noise ratio of image processing is often low, and results require significant smoothing for meaningful interpretation. This work presents a new method for such measurements in which a sigma-point Kalman filter and Rauch–Tung–Striebel smoother compute a state estimate at each time step using images from two or more high-speed camera images. Markers detected in each image are treated as individual system observations, so cameras need not be synchronized nor be viewing similar features. The benefits of this approach are demonstrated with experiments of a cube in Mach 6 flow in the University of Southern Queensland’s TUSQ wind tunnel. Measured aerodynamic coefficients show strong agreement to CFD simulations also conducted as part of this work; average differences are 1.7% and 7.8% of the maximum measured forces and moments, respectively. A discussion on factors influencing the accuracy, uncertainty, and resolution of the results provides guidance to further improve the method. Moreover, this method can be extended to more complex geometry representing space debris and hypersonic vehicles.

Dynamic strain distribution monitoring and fatigue damage analysis on a 100 kW wind turbine blade based on field aerodynamic measurements

Abstract Operation and maintenance (O&amp;M) costs can account for 10%–20% of the total costs of electricity for a wind project. Structural health monitoring method is a form of preventive maintenance consisting of regular monitoring of the wind turbine components to detect potential faults. The strain measurements on the blades are typically used for load monitoring and damage detection, but only obtain a small amount of concentrated load information. In this work, a strain distribution monitoring method was proposed and validated based on aerodynamic measurements in the field. Then the contribution and evolution of the strain distribution from the aerodynamic load, gravity load, inertial load, and centrifugal load in the complex start-up process of the wind turbine were analyzed. The results shows that the mean value of the synthetic strain is mainly determined by the aerodynamic load and the centrifugal load, while the fluctuation amplitude is mainly determined by the gravity and the aerodynamic load. Furthermore, the fatigue damage of the blade root was evaluated based on strain extrapolation, rainflow cycle-counting algorithm, Goodman diagram and Miner’s linear superposition principle. It is found that the fatigue damage is generally greatest near the pressure side and suction side, and least near the leading edge and trailing edge. The strain distribution monitoring method can capture the location of maximum stress and the most severe fatigue damage on the blade, which are helpful for damage detection and load control, and further reduces O&amp;M costs.

Experimental and computational study of aerodynamic loads on the NATO Generic Destroyer

This paper describes a detailed study into the aerodynamic loading of a 150 m long conceptual combat ship known as the NATO Generic Destroyer. Results are presented from a wind tunnel experiment in which the drag and side forces, and the roll and yaw moments, were measured around the 360° azimuth using a 0.75 m long model of the ship. Surface pressures were also measured between 0° and 180°, using 252 pressure taps distributed over the surface of the ship. The measured loads and surface pressures are shown to agree reasonably well, for most wind directions, with those predicted by a steady RANS CFD method. An unexpected result was found in the drag measurements, whereby the force was found to be towards the stern for wind directions up to 120°, i.e., with a wind component towards the bow. The reason for this apparent anomaly was explained by considering the flow field and the surface pressures acting on the ship for wind angles between 90° and 135°. The primary purpose of the paper is to make available a set of high-quality aerodynamic load measurements for a well-defined ship geometry, which is freely accessible, thereby providing a test case for CFD validation.

Predicting the impact of wind turbine noise: general overview and results of the PIBE project

The PIBE project aims to improve wind turbine noise prediction methods and to explore new solutions for noise reduction. This five years project brought together French experts in aeroacoustics, sound propagation, experimental noise characterization and wind engineering, and was structured around three work packages. The first one aimed to study amplitude modulation phenomena and focused particularly the characterization of dynamic stall noise. Specific aerodynamic and acoustic measurements were carried out in a wind tunnel, showing the influence of several stall regimes on noise production. The second work package focused on quantifying the uncertainties of noise prediction methods. It developed an open-access online application (WindTUNE) that quantifies uncertainties on noise prediction of a wind farm, and a parametric and uncertainties calculation tool for the engineering application Code-TYMPAN. This axe also produced an open-access database of a 400 days campaign of meteorological and acoustical measurements around a wind farm. The last work package investigated new noise reduction devices using blades with modified leading and/or trailing edges. The efficiency of the solutions were characterized in a wind tunnel, both acoustically and aerodynamically. The paper presents the main results obtained at the end of the project.

Aeroacoustic and aerodynamic measurements at the rotor plane in the interaction of a small rotor with wings.

Current research on tiltrotor noise predominantly concentrates on configurations with high disk loading and Reynolds numbers, leaving smaller aircraft setups underexplored. This study investigates aeroacoustic and aerodynamic trends resulting from rotor-wing interaction at low disk loading (<100 N/m2) and Reynolds number (Re < 100 000). The experimental setup comprises an anechoic chamber housing a two-blade rotor, flat and National Advisory Committee for Aeronautics 0012 airfoil wings, an ATI mini 40 load cell for aerodynamic data acquisition, and microphones positioned at the rotor height and installed on a rotation stage for acoustic data capture and directivity check. Investigated factors encompass rotor height, rotation direction, revolutions per minute (RPM), and wing curvature. Contrary to expectation, wing curvature does not visibly impact rotor performance. However, the deflected rotor wake in rotor-wing interaction markedly amplifies low-frequency broadband noise and the overall sound pressure level for the tested scenarios. The presence and strength of the deflected rotor wake tend to obscure the primary tonal noise and mitigate the effect of rotor RPM at smaller rotor spacings. This study provides valuable insights into mitigating noise resulting from rotor wake impingement on the wing in smaller aircraft configurations, contributing to the ongoing evolution of urban air mobility design considerations.

Analysis of therapeutic effect of fibrocystic degeneration of vocal folds

Objective:To explore the differences in clinical presentation and therapeutic outcomes between vocal fold fibrocystic degeneration and other common benign lesions, such as vocal fold polyp and cyst. Methods:Vocal function was assessed before and after surgery in 10 cases of vocal fold fibrocystoids, 30 cases of vocal fold polyps and 10 cases of vocal fold cysts at Department of Voice Medicine, Xiamen University Zhongshan Hospital. The voice Assessments included GRBAS（G-scale）, VHI-10 scale, Reflux Symptom Index（RSI） scale, stroboscope, acoustic objective analysis, and aerodynamics measurements. The acoustice analysis parameters included fundamental frequency（F0）, fundamental frequency perturbation（Jitter）, amplitude perturbation（Shimmer） and voice disturbance severity index（DSI）, while the maximum phonation time（MPT） was assessed for aerodynamics. Stroboscopic parameters included vocal fold straightness, vocal fold color, glottic closure and mucosal wave. All three groups underwent phonomicrosurgery and a follow-up review was conducted one month later. Pre-and post-operative function assessment parameters were compared across the three groups. Results:Significant differences were founded in the G grade, Jitter, Shimmer, DSI, glottic closure and mucosal wave between the vocal fold fibrocystic degeneration group and the vocal fold polyp and vocal fold cyst group（P<0.05）. Most voice function parameters in all three groups showed significant improvement after surgery（P<0.05）. The improvement of VHI（10）, RSI and mucosal wave scores in the vocal fold fibrocystic lesion group was significantly different from that of the vocal fold polyp group（P<0.05）. Conclusion:Vocal fold fibrocystic degeneration is a more severe than that of vocal fold polyps and cysts, which are two common benign vocal fold lesions. Phonomicrosurgery is an effective treatment for vocal fold fibrocystic degeneration, but its curative effect are less favorable compared to those for vocal fold polyps and vocal fold cysts. Therefore, a detailed preoperative evaluation is essential for predicting surgical outcomes.

Feasibility of Intensive Voice Therapy for Pediatric Vocal Fold Nodules Delivered via Telepractice: Pilot Study

PurposeThe aim of this study is to assess the feasibility of an intensive voice therapy delivered via telepractice for pediatric vocal fold nodules (VFNs). MethodTen children with VFNs (mean age = 6 years, range = 5-8 years) were recruited in this study. Assessments including stroboscopic ratings, acoustic parameters, aerodynamic and auditory perceptual measures, and parent-reported Pediatric Voice Handicap Index were administered pretreatment and within 1 week post treatment. Eight resonant voice therapy sessions were provided three times a week via a secure online platform, which were completed within 3 weeks. The assessments were conducted in a clinical face-to-face modality in China, whereas the therapy sessions were all conducted online, with the participants and their caregivers in China and the speech-language pathologist in Taiwan. ResultsAll participants completed the therapy sessions as scheduled, and there were no dropouts. Statistical analyses showed that significant improvements in acoustic and aerodynamic parameters, as well as stroboscopic and auditory-perceptual ratings. ConclusionThis study provides positive preliminary results indicating intensive voice therapy delivered via telepractice may be feasible and effective for the pediatric VFN population. Service providers and families may consider this delivery modality for ease of access when voice therapy is recommended.

Development and Design Validation of an Inflow-Settling Chamber for Turbomachinery Test-Benches

At Leibniz University of Hannover, Germany, a new turbomachinery test facility has been built over the last few years. A major part of this facility is a new 6 MW compressor station, which is connected to a large piping system, both designed and built by AERZEN. This system provides air supply to several wind tunnel and turbomachinery test rigs, e.g., axial turbines and axial compressors. These test rigs are designed to conduct high-quality aerodynamic, aeroelastic, and aeroacoustic measurements to increase physical understanding of steady and unsteady effects in turbomachines. One primary purpose of these investigations is the validation of aerodynamic and aeroacoustic numerical methods. To provide precise boundary conditions for the validation process, extremely high homogeneity of the inflow to the investigated experimental setup is imminent. Thus, customized settling chambers have been developed using analytical and numerical design methods. The authors have chosen to follow basic aerodynamic design steps, using analytical assumptions for the inlet section, the “mixing” area of a settling chamber, and the outlet nozzle in combination with state-of-the-art numerical investigations. In early 2020, the first settling chamber was brought into operation for the acceptance tests. In order to collect high-resolution flow field data during the tests, Leibniz University and AERZEN have designed a unique measurement device for robust and fast in-line flow field measurements. For this measurement device, total pressure and total-temperature rake probes, as well as traversing multi-hole probes, have been used in combination to receive high-resolution flow field data at the outlet section of the settling chamber. The paper provides information about the design process of the settling chamber, the developed measurement device, and measurement data gained from the acceptance tests.

Demystifying Velopharyngeal Dysfunction for Plastic Surgery Trainees Part 3: Objective Assessment and Surgical Decision-Making.

Velopharyngeal dysfunction (VPD) is the inability to achieve proper closure of the velopharyngeal (VP) port, affecting speech and swallowing. After an auditory-perceptual speech evaluation by a speech-language pathologist, objective assessment of the VP port is required to determine the need for surgical intervention. This 3-part series provides a comprehensive discussion on (1) the anatomy and physiology of the velopharyngeal mechanism; (2) fundamental speech terminology and principles of perceptual speech assessment for VPD; and (3) techniques for objective evaluation of the VP port and surgical decision-making process. In part 3, the authors focus on the modalities for objective VP port assessment, including both direct and indirect methods. Direct imaging techniques such as videofluoroscopy, nasoendoscopy, and MRI are detailed for their strengths and limitations in visualizing VP port function and preoperative planning. Indirect assessments, including nasometry and aerodynamic measurements, are also briefly discussed. The decision-making process for surgical intervention is explored, emphasizing factors such as the severity and etiology of VPD, VP closure patterns, palatal length, orientation of the levator veli palatini, and other patient-specific considerations. The authors review the surgical options for repair including palatoplasty procedures (Furlow palatoplasty, straight-line intravelar veloplasty, and palatal lengthening buccal myomucosal flaps) and pharyngoplasty procedures (posterior pharyngeal flaps and sphincter pharyngoplasty), highlighting their indications, techniques, and potential complications. This series serves as an accessible resource, providing the foundational knowledge required for surgical trainees new to this topic.

Experimental Study on the Endwall Aerothermal Performance of Turbine Cascades in a Novel Transient Test Facility

Abstract Linear turbine cascades have been widely used to conduct fundamental and applied investigations, but only a few transient test facilities with the linear turbine cascade are available in the open literature. A novel transient test facility was presented in this paper, including detailed design and structure, and various experimental measurements (aerodynamic and thermodynamic) were conducted to verify the transient test facility’s capability. This test facility mainly includes a main air supply line (bypass line and test line), a coolant supply line, a test section, and a control system (heater and various valves). The linear cascade holds up six equally spaced cascade profiles, forming five completed cascade passages, and the center passage is used for aerodynamic and thermodynamic measurements. The aerodynamic loss and heat transfer performance were measured at various flow conditions (incidence angle, Ma, and blowing ratio (BR)). The endwall heat transfer coefficient and film cooling effectiveness were estimated by adopting a dual linear regression technique. Results indicate that the mianstream pressure and temperature present a desired step change, and remain relatively steady in the test window. The magnitudes of endwall heat transfer significantly increase as the Maex increases from 0.2 to 0.5, but the thermal load distributions remain the same. The BR is a key parameter for endwall film cooling performance, and the optimal film cooling coverage is acquired at the critical value of BR. Both insufficient and excessive coolant flowrate can result in undesirable endwall film cooling coverage, and may cause unnecessary consumption of the coolant flow.

Influence of Carnatic Vocal Training on Voice Measures in Males

Introduction: Training is an integral part of learning any skill. The vocal training helps singers attain proficiency as they are the most demanding vocal group of all professional voice users. Hence, it is necessary to evaluate the influence of training on the singer’s voice. The current study objective was to investigate the influence of vocal training on voice measures (acoustic and aerodynamic) between male Carnatic singers with lower (6 months–5 years) and higher (6–10 years) training using novel task “mkaram” along with lyrical task. Methods: Group 1 consisted of 30 trained male Carnatic singers with lower vocal training, and group 2, thirty trained male singers with higher training in the age of 18–45 years. The acoustic (frequency-related parameter, cepstral, spectral, perturbation, and noise) and aerodynamic measures (maximum phonation time and s/z ratio) of voice were obtained. The test-retest reliability was conducted on a sample of 10% of the population from each group, with a 2-week interval between the tests. Cross-sectional study design was applied. Results: The statistical analysis revealed significantly decreased frequency-related parameters (semitones) such as the mean fundamental frequency, lowest fundamental frequency, highest fundamental frequency at the low register and the highest fundamental frequency at the middle register in group 2 during “mkaram” task (p ≤ 0.05). Similarly, one of the spectral-related measures 1st harmonic-2nd harmonic (dB) during lyrical task and one of the noise-related measure harmonic-to-noise ratio (dB) at the middle register during “mkaram” task showed a significant decrease in group 2 compared to group 1 (p ≤ 0.05). Test-retest reliability revealed that most of the parameters had “acceptable to excellent” internal consistency (Cronbach’s α >0.7 to 1). Conclusion: Few frequency and noise measures during “mkaram” task and a spectral measure during lyrical task showed to be sensitive in distinguishing the impact of vocal training on the voices of male Carnatic singers. The higher vocal training was found to help the singers to perform more efficiently with enhanced vocal range particularly in the low register and to some extent in the middle register. Indeed, the study highlighted the positive effects of vocal training on male Carnatic singers.

Numerical investigation on the tracer followability of nitrogen droplets over the airfoil in cryogenic wind tunnel

Cryogenic wind tunnels (CWT) achieve high Reynolds number aerodynamic performance measurements by cooling the medium with liquid nitrogen. Utilization of naturally-occurring liquid nitrogen droplets as tracer particles for non-intrusive measurement applications in CWT shows great potential in the previous work. However, the droplet motion characteristics over the airfoil remain to be investigated, and the followability evaluation approach is lacking. Accordingly, an Euler-Lagrange model for transonic particle flow over the NACA0012–64 airfoil was established. The effect of flow characteristics on the particle motion was explored. The results reveal that the flow separation and shock wave phenomenon over the airfoil causing velocity deviation between airflow and droplet. The shock wave is the main deviation driver, and flow separation causing trace blind zones. Droplets larger than 10 μm fail to effectively follow the variation of airflow. The blind zone enlarges with angle of attack (AoA), particularly when AoA exceeding 10 degrees. Moreover, Stokes number is found to be inadequate for characterizing the followability of tracer particles in turbulent flow. Consequently, an evaluation method based on the Basset-Boussinesq-Oseen equation was developed. This research provides theoretical and technical support for advancing the use of nitrogen droplets as tracer particles in CWT.

Correlation of Multiple Measures of Voice Evaluation Among Individuals with Muscle Tension Dysphonia: An Exploratory Study.

Primary Muscle Tension Dysphonia (MTD) occurs in the absence of structural or neurologic etiologies. Patients with MTD are frequently encountered in clinics and are evaluated using multiple measures of voice evaluation. Studies reporting on the correlation of multiple measures of voice evaluation among individuals with MTD are minimal, which led to this study. This single-group correlational study involved 48 participants diagnosed with primary MTD at a tertiary care institute. Multidimensional measures of voice (acoustic, aerodynamic, auditory-perceptual, and self-rating) were obtained from the participants. GRBAS scale, Acoustic Voice Quality Index, Acoustic Breathiness Index, Maximum Phonation Duration, S/Z ratio, Voice Handicap Index, and Vocal Fatigue Index were the variables considered. These measures were correlated using Spearman's correlation (ρ) within and between different measures of voice evaluation. Several statistically significant (P < 0.05) correlations were found within and across different measures of voice evaluation. Moderate to very high correlations (ρ between 0.48 and 0.87) were found between auditory-perceptual measures and multiparametric acoustic measures. Weak to moderate correlations (ρ between 0.31 and 0.62) were observed between the VHI and its subsections, with GRBAS, AVQI, and ABI. No statistically significant correlations were observed between aerodynamic measures and other measures of voice evaluation. Results from this study suggest that compared to across measures, the correlation between different variables was stronger within each measure of voice evaluation. These findings highlight the need for a multidimensional voice evaluation in patients with MTD.

Evaluation of Pediatric Posterior Glottic Diastasis Using Dynamic Voice Computed Tomography.

Posterior glottic diastasis (PGD) is an underappreciated etiology of dysphonia in patients with prior airway reconstruction or prolonged intubation. In endoscopic posterior cricoid reduction (ePCR), cricoid is removed to minimize the posterior glottic gap. Dynamic voice computed tomography (DVCT) permits visualization of the posterior glottis, estimating the amount of cricoid to be removed. Posterior glottic gaps in patients undergoing ePCR were compared to non-dysphonic patients to describe pediatric PGD and establish surgical parameters for ePCR. DVCTs performed in non-dysphonic patients and dysphonic patients undergoing ePCR from 2014 to 2023 were reviewed. EPCR operative reports were queried. Pre- and postoperative Pediatric Voice Handicap Index (pVHI) and Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scores and aerodynamic measures were reviewed. Seventeen pediatric patients who underwent ePCR and 19 non-dysphonic patients were included. Posterior glottic gaps were significantly larger in the dysphonic group (median 2.4 mm [IQR: 2.0, 2.8] vs. 1.3 mm [IQR: 1.1, 1.7], p < 0.001). Mean width of the cricoid removed was 1.6 mm (SD 0.4 mm). Mean (SD) pre- and postoperative pVHI scores were 55.5 (19.9) and 34.6 (16.0; p < 0.001). Mean (SD) pre- and postoperative CAPE-V scores were 52.7 (15.4) and 36.5 (20.4; p < 0.001), respectively. Children in this cohort tolerated an average 1.3 mm posterior glottic gap without dysphonia. Dysphonic patients with PGD had a median 2.4 mm gap and underwent cricoid reduction by 1.6 mm. All ePCR patients demonstrated improvement in dysphonia. Results seek to optimize the management of pediatric PGD and present a safe and effective amount of cricoid to remove during ePCR. 4 Laryngoscope, 134:5139-5144, 2024.

Aerodynamic optimization of high-rise building with façade ribs through CFD-based multi-objective optimization algorithm

Façade appurtenances is an effective aerodynamic optimization measure for alleviating the wind loads on high-rise buildings in modern cities, while the optimized layout of façade ribs necessary for practical engineering remains unclear. The conventional method through numerical simulations and wind tunnel tests can only obtain limited optimal schemes of ribs, the optimization process is time-consuming and laborious, an optimization algorithm can be used to effectively evaluate the optimal arrangement of façade ribs. In present study, a multi-objective optimization procedure coupling large eddy simulation (LES), back propagation neural network (BPNN), and non-dominated sorting genetic algorithm (NSGA-II) is applied to evaluate the optimal arranged parameters of façade vertical ribs. The optimization procedure can quickly identify the optimal location parameter b and extensional depth d of façade ribs that producing minimum wind loads acting on building and ribs. The findings indicate that there are complex non-linear relationships between the ribs arrangement parameters and the objective wind loads. The mean drag C‾d and fluctuating lift C'l of models of windward ribs and upstream sidewall ribs have opposite trend. The relationships between wind forces and arranged parameters of the downstream sidewall and leeward ribs are relatively complicated due to the vortex shedding. Genetic algorithm NSGA-II can effectively evaluate the optimal trade-off solution among multi-objective wind loads. The ranges of optimal layout parameters b/D and d/D are 0.14–0.17, 0.073–0.077, the ratio of b/d is about 2, and the optimal arrangement of façade ribs well balances the total wind forces on the model and wind forces on the ribs. The 3D numerical simulations demonstrate that the optimal layout of the ribs can considerably improve the flow structure and wind load, the maximum reduction ratio of the C‾d and C'l are achieved 25 % and 56 %, respectively. The obtained optimized layout parameters can provide reference for engineers when actually using the facade ribs.