# Aerodynamics and Fluid Mechanics Commons™

## All Articles in Aerodynamics and Fluid Mechanics

601 full-text articles. Page 1 of 27.

2019 AAR Aerospace Consulting, LLC

#### Estimation Of Performance Airspeeds For High-Bypass Turbofans Equipped Transport-Category Airplanes, Nihad E. Daidzic

##### Nihad E. Daidzic, Dr.-Ing., D.Sc., ATP, CFII, MEI

Conventional Mach-independent subsonic drag polar does not replicate the real airplane drag characteristics exactly and especially not in the drag-divergence region due to shock-induced transonic wave drag. High-bypass turbofan thrust is a complicated function of many parameters that eludes accurate predictions for the entire operating envelope and must be experimentally verified. Fuel laws are also complicated functions of many parameters which make optimization and economic analysis difficult and uncertain in the conceptual design phase. Nevertheless, mathematical models and predictions have its important place in aircraft development, design, and optimization. In this work, airspeed-dependent turbofan thrust and the new fuel-law model ...

Efficient General Computational Method For Estimation Of Standard Atmosphere Parameters, 2019 AAR Aerospace Consulting, LLC

#### Efficient General Computational Method For Estimation Of Standard Atmosphere Parameters, Nihad E. Daidzic Ph.D., Sc.D.

##### Nihad E. Daidzic, Dr.-Ing., D.Sc., ATP, CFII, MEI

Knowledge of standard air temperature, pressure, density, speed of sound, and viscosity as a function of altitude is essential information in aircraft design, performance testing, pressure altimeter calibration, and several other aeronautical engineering and aviation science applications. A new efficient computational method for rapid calculations of standard atmospheric parameters up to 86 orthometric km is presented. Additionally, mass and weight of each standard atmospheric layer were calculated using a numerical integration method. The sum of all fractional masses and weights represents the total mass and weight of Earth’s atmosphere. The results obtained here agree well with measurements and models ...

Achieving Global Range In Future Subsonic And Supersonic Airplanes, 2019 AAR Aerospace Consulting, LLC

#### Achieving Global Range In Future Subsonic And Supersonic Airplanes, Nihad E. Daidzic Ph.D., Sc.D.

##### Nihad E. Daidzic, Dr.-Ing., D.Sc., ATP, CFII, MEI

No commercial airplane in service today is able to fly half great-circle distances over the globe and achieve the non-stop or the global range to any antipodal location on Earth. A subsonic jetliner has the optimum cruising speed at Mach numbers approaching the drag divergence Mach number while still preserving relatively high aerodynamic efficiency. Various fuel-flow laws were used to investigate the cruise performance of subsonic and supersonic aircraft. The effect of wind and aircraft weight and how it affects the optimal cruising airspeed was investigated. Of all different operational cruising techniques, the cruise-climb at high Mach numbers is the ...

2019 AAR Aerospace Consulting, LLC

#### A Contribution Toward Better Understanding Of Overbanking Tendency In Fixed-Wing Aircraft, Nihad E. Daidzic

##### Nihad E. Daidzic, Dr.-Ing., D.Sc., ATP, CFII, MEI

The phenomenon of overbanking tendency for a rigid-body, fixed-wing aircraft is investigated. Overbanking tendency is defined as a spontaneous, unbalanced rolling moment that keeps increasing an airplane’s bank angle in steep turns and must be arrested by opposite aileron action. As stated by the Federal Aviation Administration, the overbanking tendency may lead to a loss of control, especially in instrument meteorological conditions. It was found in this study that the speed differential over wing halves in horizontal turns indeed creates a rolling moment that achieves maximum values for bank angles between 45 and 55 degrees. However, this induced rolling ...

Autonomous Watercraft Simulation And Programming, 2019 Lynchburg College

#### Autonomous Watercraft Simulation And Programming, Nicholas J. Savino

##### Undergraduate Theses and Capstone Projects

Automation of various modes of transportation is thought to make travel more safe and efficient. Over the past several decades advances to semi-autonomous and autonomous vehicles have led to advanced autopilot systems on planes and boats and an increasing popularity of self-driving cars. We simulated the motion of an autonomous vehicle using computational models. The simulation models the motion of a small-scale watercraft, which can then be built and programmed using an Arduino Microcontroller. We examined different control methods for a simulated rescue craft to reach a target. We also examined the effects of different factors, such as various biases ...

2019 Washington University in St. Louis

#### Development Of A One-Equation Turbulence Model Based On K-Ε Closure And Its Extension For Computing Transitional Flows By Including An Intermittency Transport Equation, Cheng Peng

##### Engineering and Applied Science Theses & Dissertations

No abstract provided.

2019 Embry-Riddle Aeronautical University

#### Experimental And Computational Analysis Of A 3d Printed Wing Structure, Aryslan Malik

##### Dissertations and Theses

Correct prediction of aeroelastic response is a crucial part in designing flutter or divergence free aircrafts within a designated flight envelope. The aeroelastic analysis includes specifically tailoring the design in order to prevent flutter (passive control) or eliminate it by applying input on control surfaces (active control). High-fidelity models such as coupled Computational Fluid Dynamics (CFD) - Computational Structural Dynamics (CSD) can obtain full structural and aerodynamic behavior of a deformable aircraft. However, these models are so large that pose a significant challenge from the control systems design perspective. Thus, the development of an aeroelastic modeling software that can be used ...

Preliminary Test Predictions For Scale Ram-Air Parachute Testing, 2019 Embry-Riddle Aeronautical University

#### Preliminary Test Predictions For Scale Ram-Air Parachute Testing, Christian A. Guzman Zurita

##### Dissertations and Theses

The present thesis proposes a preliminary analysis to predict the aerodynamic performance for experimental tests of ram-air parachutes in a wind tunnel. A scaled experimental test setup is developed for determining the aerodynamic coefficients of lift (𝐶𝐿) and drag (𝐶𝐷) conducted in a wind tunnel. Additionally, a CFD approach where a steady-state parachute shape defined based on experiments, photographs, and literature, is presented. The accuracy of the simulation depends considerably on the ability to resolve the canopy geometry. Therefore, a CAD geometry generation is implemented for flexible control of the canopy structure by implementing design parameters, e.g., chord, span ...

Autonomous Watercraft Simulation And Programming, 2019 Lynchburg College

#### Autonomous Watercraft Simulation And Programming, Nicholas J. Savino

##### Student Scholar Showcase

Automation of various modes of transportation is thought to make travel more safe and efficient. Over the past several decades, advances to semi-autonomous and autonomous vehicles have led to advanced autopilot systems on planes and boats, and an increasing popularity of self-driving cars. We predicted the motion of an autonomous vehicle using simulations in Python. The simulation models the motion of a small scale watercraft, which can then be built and programmed using an Arduino Microcontroller. We examined different control methods for a simulated rescue craft to reach a target. We also examined the effects of different factors, such as ...

Sweep And Taper Analysis Of Surfboard Fins Using Computational Fluid Dynamics, 2019 California Polytechnic State University, San Luis Obispo

#### Sweep And Taper Analysis Of Surfboard Fins Using Computational Fluid Dynamics, Brandon James Baldovin

##### Master's Theses and Project Reports

The research presented here provides a basis for understanding the hydrodynamics of surfboard fin geometries. While there have been select studies on fins there has been little correlation to the shape of the fin and its corresponding hydrodynamic performance. This research analyzes how changing the planform shape of a surfboard fin effects its performance and flow field. This was done by isolating the taper and sweep distribution of a baseline geometry and varying each parameter individually whilst maintaining a constant span and surface area. The baseline surfboard fin was used as a template in Matlab to generate a set of ...

2019 Cal Poly-San Luis Obispo

#### A Higher-Order Method Implemented In An Unstructured Panel Code To Model Linearized Supersonic Flows, Jake Daniel Davis

##### Master's Theses and Project Reports

Since their conception in the 1960s, panel codes have remained a critical tool in the design and development of air vehicles. With continued advancement in computational technologies, today's codes are able to solve flow fields around arbitrary bodies more quickly and with higher fidelity than those that preceded them. Panel codes prove most useful during the conceptual design phase of an air vehicle, allowing engineers to iterate designs, and generate full solutions of the flow field around a vehicle in a matter of seconds to minutes instead of hours to days using traditional CFD methods. There have been relatively ...

2019 Lehigh University

#### An End-To-End Platform For Autonomous Dynamic Soaring In Wind Shear, Corey Montella

##### Theses and Dissertations

Despite advancements in our understanding of flight in modern times, birds remain unmatched when it comes to maneuverability and energy efficiency in flight; in particular seabirds like the albatross are known to travel vast distances without stopping for food by performing an aerobatic maneuver called dynamic soaring. When the maneuver is executed in the presence of a wind field that varies in strength of direction, the albatross extracts kinetic energy from the field. In this dissertation, we present an end-to-end system designed to exploit wind as the albatross does. The system we designed consists of a gliding platform outfitted with ...

Scaling Analysis And Experimental Investigation Of A Rotating Detonation Engine, 2019 West Virginia University

#### Scaling Analysis And Experimental Investigation Of A Rotating Detonation Engine, David Thomas Billups

##### Graduate Theses, Dissertations, and Problem Reports

Pressure gain combustion (PGC) technologies, specifically rotating detonation engines (RDEs), are poised to provide the next big leap in gas turbine engine advancement, significantly increasing the thermal. RDEs make use of thermodynamic advantages of isochoric as opposed to isobaric combustion. Theorized to increase thermal efficiency by up to 7% [1], the RDE would have significant impact on reducing anthropogenic carbon emissions. In addition to efficiency gains, the RDE also provides mechanical simplicity and reduced size advantages compared to it’s traditional counterparts and PGC competition.

The United States (U.S.) Department of Energy (DOE) National Energy Technology Laboratory (NETL) maintains ...

Generator Design: A Study Of Optimized Airflow, 2019 The University of Akron

#### Generator Design: A Study Of Optimized Airflow, Rachel Wattleworth

##### Williams Honors College, Honors Research Projects

The core goal of this project was to prototype, test, and evaluate a new type of fan for the Safran Electrical & Power air-cooled generators. The idea of a new fan being made for these two generators arose when they were not adhering to design requirements. A base mixed-flow fan was created to test on multiple generators. Upon creating a prototype, it will be tested to prove if it can increase the air flow, decrease temperatures, and increase power and life of the machines. They all proved to be successful and achieve the main objectives for this project. Data such as ...

Space Dynamics Laboratory Payload Challenge: Autonomous Water Sampling Uav, 2019 The University of Akron

#### Space Dynamics Laboratory Payload Challenge: Autonomous Water Sampling Uav, Thomas Wheeler, Zachary Williams, Joseph Stack

##### Williams Honors College, Honors Research Projects

The following report has been completed over the course of the Fall 2018 and Spring 2019 semesters at The University of Akron by Joseph P. Stack (Aerospace Systems Engineering), Thomas J. Wheeler (Mechanical Engineering) and Zachary M. Williams (Mechanical Engineering). The purpose of this project was to create a payload system for the Akronauts Rocket Design Team to use at the Intercollegiate Rocket Engineering Competition (IREC) Spaceport America Cup. The Competition as a challenge that is sponsored by Space Dynamics Laboratory specifically regarding payload systems. The challenge in very open-ended and allows student to identify their own scientific experiment and ...

A New Method For The Prediction Of The Downwash Angle Gradient, 2019 Ecole d'aviation de Borj El Amri, Tunisia.

#### A New Method For The Prediction Of The Downwash Angle Gradient, Mondher Yahyaoui Dr.

##### International Journal of Aviation, Aeronautics, and Aerospace

A new method for the prediction of the downwash angle gradient due to aircraft wings across the span of an aft horizontal tail in the incompressible regime is presented. The approach is quite general and accounts for all practical wing geometric parameters except for wing twist where it is shown that this parameter has very little effect on the downwash angle gradient. The method consists of an empirical law which requires the prior knowledge of three constants. These have been computed either based on experimental data when available or using numerical data obtained using the vortex-lattice method. These constants are ...

2019 Embry-Riddle Aeronautical University

#### Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins

##### International Journal of Aviation, Aeronautics, and Aerospace

The Federal Aviation Administration (FAA) has put forth a set of regulations (Part 107) that govern small unmanned aerial system (sUAS) operations. These regulations restrict unmanned aircraft (UA) from flying over people and their operation to within visual line of sight (VLOS). However, as new applications for unmanned aerial systems (UAS) are discovered, their capabilities improve, and regulations evolve, there is an increasing desire to undertake urban operations, such as urban air mobility, package delivery, infrastructure inspection, and surveillance. This built environment poses new weather hazards that include enhanced wind shear and turbulence. The smaller physical dimensions, lower mass and ...

Computational Study Of Flow Interactions Over A Close Coupled Canard-Wing On Fighter, 2019 Universitas Gadjah Mada, Indonesia

#### Computational Study Of Flow Interactions Over A Close Coupled Canard-Wing On Fighter, Setyawan Bekti Wibowo, Sutrisno Sutrisno, Tri Agung Rohmat

##### International Journal of Aviation, Aeronautics, and Aerospace

There have been many attempts to improve the flying performance of a fighter. By modifying the flow that occurs along the fuselage is expected to improve the performance of the aircraft. One of the indicators of combat aircraft performance is the ability to perform maneuver movement. Adding a canard as forewing on the fighter wing configuration is considered capable of raising the ability in maneuver movement. The use of canard-delta pairs will affect the performance and aerodynamic characteristics of the plane. Wings and canards with delta configuration will make the rolled-up vortex as a lifting force producer on the aircraft ...

2018 University of Nevada, Las Vegas

#### Cfd Modeling Of Smoke Movement In An Atrium, Robin Wu

##### UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this paper is to better understand the behavior of smoke movement in an atrium. Thus gives first responders and civilians in and out of building a better understanding

With the advancements of modern technology, computers and softwares make simulation models possible such as fire models to simulate fire and smoke movements. In this paper, a computational fluid dynamic (CFD) software Fire Dynamic Simulator (FDS) is used to conduct a series of atrium tests to investigate the effectiveness of smoke exhaust systems. FDS solves the Navier-Stokes equations appropriate for low speed flows (Ma < 0.3) with an emphasis on smoke, heat transport and CO2 concentrations from fires. The default turbulence model used in FDS simulation is the Large Eddy Simulation (LES), which is the solution of Navier-Stokes equations at low speed.

The compartment tested was 9 ...

Rotating Mount For Complex Fluid Flow Research, 2018 Western Michigan University

#### Rotating Mount For Complex Fluid Flow Research, Kirsten Murphy

##### Honors Theses

Fluid flow around rotating objects is mathematically complex and there is currently limited experimental data on the subject. To make Western Michigan University capable of this research, a rotating wind tunnel mount was developed. The mount design was integrated into the existing setup at the Applied Aerodynamics Laboratory (AAL) to allow seamless transitions between different research projects. Non-rotating and rotating disk prototypes were created from 3D-printed materials to test the mount’s capabilities. Experimental data gathered from utilizing this rotating mount was analyzed to understand the aerodynamic effects on rotating disks in a fluid stream. From testing the rotating disk ...