The design of an aircraft wing often involves the use of mathematical methods for simultaneous aerodynamic and structural design. The goal of many of these methods is to minimize the drag on the wing. A variety of computer models exist for this purpose, but some require the use of expensive time and computational resources to give meaningful results. As an alternative, some mathematical methods have been developed that give reason ably accurate results without the need for a computer. However, most of these methods can only be used for wings with specific shapes and payload distributions. In this thesis, a hybrid mathematical/computational approach to wing design is developed that can be used for wings of any shape with any payload distribution. Specific mathematical expressions are found to predict the weight and drag for tapered wings and elliptic-shaped wings. The new approach and mathematical expressions are used to find the best distribution of lift on a variety of aircraft wing configurations to minimize drag during flight.

Several programs exist today for calculating aerodynamic coefficients that with some simplifications provide fast approximations of the values for a real aircraft. Four different programs were analyzed for this report: Tornado, AVL, PANAIR and a handbook-type preliminary method. In addition, ANSYS CFX was used for airfoil validation. For calculation of the zero lift drag, an approximation was computed in order to calculate the remaining values that were not calculated by the software: drag contribution for fuselages, nacelles and some horizontal stabilizers and fins. Different types of aircraft were selected for trial: two commercial aircraft (Boeing 747-100 and 777-300), a TF-8A research airplane (with area rule application: some additions were made to the fuselage to prevent large variations in the cross-section when the contribution of the wing is  added), a Lockheed Constellation C-69 u sed as a military cargo airplane, a Boeing Stratocruiser used by the USAF with two configurations (basic and bomber), and an Aero Commander 680 Super, similar to a Cessna 162. Two airfoils (NACA2412, 0012) were also analyzed, to investigate the limitations of software designed for three-dimensional calculations. The accuracy of the results showed that the validity of the software depends on the planform of the aircraft, as well as the simulation parameters Mach number and Reynolds number. The shape of the wing caused some of the methods to have serious difficulties in converging to valid results, or increased the simulation time beyond acceptable limits. / Numera finns det olika program för beräkning av de aerodynamiska koefficienterna från en modell med vissa förenklingar som ger en snabb approximation av värdena för ett verkligt flygplan. Fyra olika program har analyserats för denna rapport: Tornado, AVL, PANAIR och en handbok baserad preliminär metod. Dessutom användes ANSYS CFX för validering av vingprofiler . Vid beräkningen av noll-lyft motståndet, en approximation användes för de återstående delarna som inte beräknas av de andra metoderna: motståndsbidraget från flygkroppar, gondoler och vissa horisontella stabilisatorer och fenor. Olika flygplaner har testats: två trafikflygplan (Boeing 747-100 och 777-300), ett TF-8A forskningsflygplan (med area regel användning: några tillägg gjordes på flygkroppen för att tvärsnitten inte har stora variationer när bidraget från vingen läggas), ett Lockheed Constellation C-69, ett Boeing Stratocruiser som används av USAF i två konfigurationer (den vanliga och bombplan), och ett Aero Commander 680 Super, som liknar ett Cessna 162. Två vingprofiler (NACA 2412, 0012) analyserades också, för att kontrollera begränsningarna av programmen avsedd för tredimensionella beräkningar. Riktigheten av resultaten visade att giltigheten av programmen beror på formen av flygplanernas vingar, samt de simulationernas parametrar: Mach nummer och Reynolds nummer. Formen på vingen orsakade några av de metoderna att ha stora svårigheter med konvergensen till giltiga resultat, eller ökat simulering tid över acceptabla gränser.

Thesis (Aeronautical and Astronautical Engineer)--Naval Postgraduate School, December 2002. / Thesis advisor(s): Kevin James, Max Platzer. Includes bibliographical references (p. 139). Also available online.

A Newton-Krylov algorithm is presented for aerodynamic shape optimization in three dimensions using the Euler equations. An inexact-Newton method is used in the flow solver, a discrete-adjoint method to compute the gradient, and the quasi-Newton optimizer to find the optimum. A Krylov subspace method with approximate-Schur preconditioning is used to solve both the flow equation and the adjoint equation. Basis spline surfaces are used to parameterize the geometry, and a fast algebraic algorithm is used for grid movement. Accurate discrete-adjoint gradients can be obtained in approximately one-fourth the time required for a converged flow solution. Single- and multi-point lift-constrained drag minimization optimization cases are presented for wing design at transonic speeds. In all cases, the optimizer is able to efficiently decrease the objective function and gradient for problems with hundreds of design variables.

A Newton-Krylov algorithm is presented for aerodynamic shape optimization in three dimensions using the Euler equations. An inexact-Newton method is used in the flow solver, a discrete-adjoint method to compute the gradient, and the quasi-Newton optimizer to find the optimum. A Krylov subspace method with approximate-Schur preconditioning is used to solve both the flow equation and the adjoint equation. Basis spline surfaces are used to parameterize the geometry, and a fast algebraic algorithm is used for grid movement. Accurate discrete-adjoint gradients can be obtained in approximately one-fourth the time required for a converged flow solution. Single- and multi-point lift-constrained drag minimization optimization cases are presented for wing design at transonic speeds. In all cases, the optimizer is able to efficiently decrease the objective function and gradient for problems with hundreds of design variables.

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Purpose: An open mouth approach is used in voice therapy for enhancing speech and voice production and relaxing the laryngeal musculature. The acoustic and physiological consequences of an open jaw posture, however, have not been clearly understood due to a paucity of cross-system studies taking the age effect into consideration. The major aims of this study are twofold (1) to examine if the geriatric voice may be improved using an “open jaw” posture and (2) if an aging effect on the voice of normal healthy adults can be detected through acoustic and physiological measures Method: The main part of this study involved simultaneous multi-channel voice recordings obtained from 85 healthy adults aged between 38 and 93 years. A convenience sampling strategy was used to recruit at least five females and five males in each of four age groups, 35-59 years (35+), 60-69 (60+), 70-79 (70+), and above 80 (80+). For simultaneous acoustic, electroglottographic (EGG), and jaw displacement recordings, participants were asked to perform two tasks which included a sustained vowel task and a sentence production task. The sustained vowel task involved sustaining the vowel /a/ in five different conditions, an isolated vowel /a/ produced at normal, low, and high pitch levels and the vowel /a/ initiated with a consonant (/m/ and /h/). The sentence production task involved production of the sentence 'We saw two cars,' containing the vowels /i, ɔ, u, a/. For simultaneous airflow-EGG recordings, participants were asked to sustain the vowel /a/ at normal pitch. For simultaneous airflow-air pressure-EGG recordings, participants were asked to repeat /pa/ five times in one breath. Participants were asked to perform all of the tasks using two jaw postures (normal and open). A series of univariate analysis of variances were used to identify instrumental measures sensitive for discriminating between the four age groups and the two jaw postures. A follow-up perceptual study was conducted to determine the effect of an open jaw posture on vowel intelligibility and voice clarity. A quota sampling strategy was used to recruit 40 normal hearing participants, including 20 females (age range = 18-42 years, mean = 25.3, SD = 7.9) and 20 males (age range = 18-47, mean = 23.6, SD = 6.7). These listeners were presented with vowels segmented from the sentences recorded in the first experiment and asked to perform a vowel identification and a voice clarity discrimination task. The vowel samples were taken from 40 speakers, with five females and five males in each of the four age groups (35+, 60+, 70+, and 80+). The percentages of correct vowel identification for voices produced with normal and open jaw postures were compared. The percentages of vowels judged as 'clearer' in a normal-open jaw contrast pairs were also calculated for comparison. Results: Significant age group effects were found in this study for both genders on fundamental frequency (F0), voice onset time (VOT) (/ka/), open quotient (OQ), and speed quotient (SQ), with additional age differences detected for females on %jitter, %shimmer, signal-to-noise ratio (SNR), and the second formant frequency (F2), and for males a significant age group effect was found on VOT (/tu/). Results for both females and males revealed significant open jaw posture effects on F0, F2, VOT (/ka/), MFR, SPL and vowel space area. In addition, for females significant posture effects were found on F1, subglottal pressure and the H1-H2 amplitude difference, and for males, significant posture effects were found on %jitter and VOT-/tu/. Results from the follow-up perceptual study revealed that an open jaw posture was associated with better vowel identification and better voice clarity. Conclusions: A selection of instrumental measures was shown to be useful for detecting voice changes due to aging. Instrumental and perceptual evidence was found that an open jaw posture was associated with positive changes in vocal behaviours, including improved phonatory stability, vocal power, and voice clarity.