Surface Pressure Fluctuations Near an Axisymmetric Stagnation Point
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Chapter Sixteen / Plug, Underexpanded and Overexpanded Supersonic Nozzles ------Chapter Sixteen / Plug, Underexpanded and Overexpanded Supersonic Nozzles
UOT Mechanical Department / Aeronautical Branch Gas Dynamics Chapter Sixteen / Plug, Underexpanded and Overexpanded Supersonic Nozzles -------------------------------------------------------------------------------------------------------------------------------------------- Chapter Sixteen / Plug, Underexpanded and Overexpanded Supersonic Nozzles 16.1 Exit Flow for Underexpanded and Overexpanded Supersonic Nozzles The variation in flow patterns inside the nozzle obtained by changing the back pressure, with a constant reservoir pressure, was discussed early. It was shown that, over a certain range of back pressures, the flow was unable to adjust to the prescribed back pressure inside the nozzle, but rather adjusted externally in the form of compression waves or expansion waves. We can now discuss in detail the wave pattern occurring at the exit of an underexpanded or overexpanded nozzle. Consider first, flow at the exit plane of an underexpanded, two-dimensional nozzle (see Figure 16.1). Since the expansion inside the nozzle was insufficient to reach the back pressure, expansion fans form at the nozzle exit plane. As is shown in Figure (16.1), flow at the exit plane is assumed to be uniform and parallel, with . For this case, from symmetry, there can be no flow across the centerline of the jet. Thus the boundary conditions along the centerline are the same as those at a plane wall in nonviscous flow, and the normal velocity component must be equal to zero. The pressure is reduced to the prescribed value of back pressure in region 2 by the expansion fans. However, the flow in region 2 is turned away from the exhaust-jet centerline. To maintain the zero normal-velocity components along the centerline, the flow must be turned back toward the horizontal. -
Diagnostic Techniques for MHD in Hypersonic Flows
UNIVERSITA’ DEGLI STUDI DI BOLOGNA FACULTY OF ELECTRICAL ENGINEERING SCIENTIFIC FIELD ING‐IND/31 XXII CYCLE Diagnostic Techniques for MHD in Hypersonic Flows PhD Thesis Veronica Maria Granciu Advisor: Chiar.mo Prof. CARLO ANGELO BORGHI Second Advisor: Prof. ANDREA CRISTOFOLINI Ph.D. Coordinator: Chiar.mo Prof. FRANCESCO NEGRINI Bologna, March 2010 UNIVERSITA’ DEGLI STUDI DI BOLOGNA FACULTY OF ELECTRICAL ENGINEERING SCIENTIFIC FIELD ING‐IND/31 XXII CYCLE Diagnostic Techniques for MHD in Hypersonic Flows PhD Thesis Veronica Maria Granciu Advisor: Chiar.mo Prof. CARLO ANGELO BORGHI Second Advisor: Prof. ANDREA CRISTOFOLINI Ph.D. Coordinator: Chiar.mo Prof. FRANCESCO NEGRINI Bologna, March 2010 ACKNOWLEDGEMENTS I would like to express my heartfelt gratitude to my advisors Professor Carlo Borghi and Professor Andrea Cristofolini for excellent guidance and motivation. Their encouragement and understanding during the study has been a source of inspiration for me. My special thank belongs to my lab co‐worker Gabriele, who gave me the first live taste of the beauty plasma research. It was a very great experience to work with him. Thanks Hugo! I’m also grateful to my colleagues Chiara and Fabio, “i plasmatici”, for their suggestions and moral support. In conclusion, I wish to dedicate this work to my family and to Marco, who offer me courage, hope and a lot of patience. Without his love, I never would have made it. Thank you for believing in me. Index INTRODUCTION .............................................................................................................. 1 PART I Diagnostic procedures theory Chapter 1 Microwave Transmission System 1.1 Introduction ............................................................................................... 5 1.2 Electromagnetic waves in collisionless plasma .......................................... 5 1.3 Electromagnetic waves in collisional plasma ……………………...................... -
Normal and Oblique Shocks, Prandtl Meyer Expansion
Aerothermodynamics of high speed flows AERO 0033{1 Lecture 3: Normal and oblique shocks, Prandtl Meyer expansion Thierry Magin, Greg Dimitriadis, and Adrien Crovato [email protected] Aeronautics and Aerospace Department von Karman Institute for Fluid Dynamics Aerospace and Mechanical Engineering Department Faculty of Applied Sciences, University of Li`ege Wednesday 9am { 12:15pm February { May 2021 1 / 36 Outline Normal shock Total and critical quantities Oblique shock Prandtl-Meyer expansion Shock reflection and shock interaction 2 / 36 Outline Normal shock Total and critical quantities Oblique shock Prandtl-Meyer expansion Shock reflection and shock interaction 2 / 36 Normal shock relations (inviscid flow) Rankine-Hugoniot relations for steady normal shock σ = 0; v = u ex ; n = ex ! σn(U2 − U1) = (F · n)2 − (F · n)1 ρ2u2 = ρ1u1 2 2 ρ2u2 + p2 = ρ1u1 + p1 ρ2u2H2 = ρ1u1H1 I Eqs. also valid for non calorically perfect gases I Contact discontinuity when u2 = u1 = 0 ! p2 = p1 I Otherwise, the total enthalpy conservation can be expressed as 2 2 2 u cp p γ p2 u2 γ p1 u1 H2 = H1 with H = h+ ; h = ! + = + 2 R ρ γ − 1 ρ2 2 γ − 1 ρ1 2 I Non-linear algebraic system of 3 eqs. in 3 unknowns ρ2, u2, and p2 with closed solution expressed in function of dimensionless parameters: Machp number M1 = u1=a1 and specific heat ratio γ, with a1 = γRT1 3 / 36 Normal shock relations for calorically perfect gases For M1 > 1 (derivation given further in this section) 2 ρ2 u1 (γ+1)M1 I ρ = u = 2 > 1 1 2 2+(γ−1)M1 p2 = 1 + 2γ (M2 − 1) > 1 I p1 γ+1 1 γ−1 2 2 1+ 2 -
Introduction
CHAPTER 1 Introduction "For some years I have been afflicted with the belief that flight is possible to man." Wilbur Wright, May 13, 1900 1.1 ATMOSPHERIC FLIGHT MECHANICS Atmospheric flight mechanics is a broad heading that encompasses three major disciplines; namely, performance, flight dynamics, and aeroelasticity. In the past each of these subjects was treated independently of the others. However, because of the structural flexibility of modern airplanes, the interplay among the disciplines no longer can be ignored. For example, if the flight loads cause significant structural deformation of the aircraft, one can expect changes in the airplane's aerodynamic and stability characteristics that will influence its performance and dynamic behavior. Airplane performance deals with the determination of performance character- istics such as range, endurance, rate of climb, and takeoff and landing distance as well as flight path optimization. To evaluate these performance characteristics, one normally treats the airplane as a point mass acted on by gravity, lift, drag, and thrust. The accuracy of the performance calculations depends on how accurately the lift, drag, and thrust can be determined. Flight dynamics is concerned with the motion of an airplane due to internally or externally generated disturbances. We particularly are interested in the vehicle's stability and control capabilities. To describe adequately the rigid-body motion of an airplane one needs to consider the complete equations of motion with six degrees of freedom. Again, this will require accurate estimates of the aerodynamic forces and moments acting on the airplane. The final subject included under the heading of atmospheric flight mechanics is aeroelasticity. -
Nozzle Aerodynamics Baseline Design
Preliminary Design Review Supersonic Air-Breathing Redesigned Engine Nozzle Customer: Air Force Research Lab Advisor: Brian Argrow Team Members: Corrina Briggs, Jared Cuteri, Tucker Emmett, Alexander Muller, Jack Oblack, Andrew Quinn, Andrew Sanchez, Grant Vincent, Nathaniel Voth Project Description Model, manufacture, and verify an integrated nozzle capable of accelerating subsonic exhaust to supersonic exhaust produced from a P90-RXi JetCat engine for increased thrust and efficiency from its stock configuration. Stock Nozzle Vs. Supersonic Nozzle Inlet Compressor Combustor Turbine Project Baseline Nozzle Nozzle Test Nozzle Project Description Design Aerodynamics Bed Integration Summary Objectives/Requirements •FR 1: The Nozzle Shall accelerate the flow from subsonic to supersonic conditions. •FR 2: The Nozzle shall not decrease the Thrust-to-Weight Ratio. •FR 3: The Nozzle shall be designed and manufactured such that it will integrate with the JetCat Engine. •DR 3.1: The Nozzle shall be manufactured using additive manufacturing. •DR 3.4: Successful integration of the nozzle shall be reversible such that the engine is operable in its stock configuration after the new nozzle has been attached, tested, and detached. •FR4: The Nozzle shall be able to withstand engine operation for at least 30 seconds. Project Baseline Nozzle Nozzle Test Nozzle Project Description Design Aerodynamics Bed Integration Summary Concept of Operations JetCat P90-SE Subsonic Supersonic Engine Flow Flow 1. Remove Stock Nozzle 2. Additive Manufactured 3-D Nozzle -
Gas Dynamics and Jet Propulsion
A Course Material on GAS DYNAMICS AND JET PROPULSION By Mr. C.RAVINDIRAN. ASSISTANT PROFESSOR DEPARTMENT OF MECHANICAL ENGINEERING SASURIE COLLEGE OF ENGINEERING VIJAYAMANGALAM – 638 056 QUALITY CERTIFICATE This is to certify that the e-course material Subject Code : ME2351 Subject : GAS DYNAMICS AND JET PROPULSION Class : III Year MECHANICAL ENGINEERING being prepared by me and it meets the knowledge requirement of the university curriculum. Signature of the Author Name : C. Ravindiran Designation: Assistant Professor This is to certify that the course material being prepared by Mr. C. Ravindiran is of adequate quality. He has referred more than five books amount them minimum one is from abroad author. Signature of HD Name: Mr. E.R.Sivakumar SEAL CONTENTS S.NO TOPIC PAGE NO UNIT-1 BASIC CONCEPTS AND ISENTROPIC 1.1 Concept of Gas Dynamics 1 1.1.1 Significance with Applications 1 1.2 Compressible Flows 1 1.2.1 Compressible vs. Incompressible Flow 2 1.2.2 Compressibility 2 1.2.3. Compressibility and Incompressibility 3 1.3 Steady Flow Energy Equation 5 1.4 Momentum Principle for a Control Volume 5 1.5 Stagnation Enthalpy 5 1.6 Stagnation Temperature 7 1.7 Stagnation Pressure 8 1.8 Stagnation velocity of sound 9 1.9 Various regions of flow 9 1.10 Flow Regime Classification 11 1.11 Reference Velocities 12 1.11.1 Maximum velocity of fluid 12 1.11.2 Critical velocity of sound 13 1.12 Mach number 16 1.13 Mach Cone 16 1.14 Reference Mach number 16 1.15 Crocco number 19 1.16 Isothermal Flow 19 1.17 Law of conservation of momentum 19 1.17.1 Assumptions -
Model-Based Stagnation Pressure Control in a Supersonic Wind Tunnel
Model-Based Stagnation Pressure Control in a Supersonic Wind Tunnel Biljana Ilić Lead Research Engineer The flow parameters control in wind tunnels is an area of intense research Experimental Aerodynamics Department in recent years, with the aim of improving quality and efficiency of the Military Technical Institute Belgrade wind tunnel operation. In this paper, an attempt is made to contribute to a Marko Miloš better understanding of the stagnation pressure control in supersonic Professor blowdown-type facilities. The stagnation pressure control strategy in the University of Belgrade VTI Belgrade T-38 wind tunnel is discussed. An improved mathematical Faculty of Mechanical Engineering model for a supersonic wind tunnel is suggested and applied to the T-38 Mirko Milosavljević facility. Comparisons of simulation and experimental data are made to Lead Research Engineer demonstrate accurate prediction of the facility response in supersonic flow Experimental Aerodynamics Department conditions by the mathematical model. The model is used to incorporate a Military Technical Institute Belgrade modified feedforward control in the original T-38 wind tunnel control Jovan Isaković system. The actual wind tunnel tests confirm model-predicted decrease of flow stabilization time and increase of available measurement time, Professor Tehnikum Taurunum - College of Applied bringing significant improvement in the wind tunnel operation efficiency. Engineering Studies Belgrade Keywords: supersonic flow, mathematical model, blowdown wind tunnel, stagnation -
Unsteady Flows in a Single-Stage Transonic Axial-Flow Fan Stator Row Michael Dale Hathaway Iowa State University
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1986 Unsteady flows in a single-stage transonic axial-flow fan stator row Michael Dale Hathaway Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Mechanical Engineering Commons Recommended Citation Hathaway, Michael Dale, "Unsteady flows in a single-stage transonic axial-flow fan stator row " (1986). Retrospective Theses and Dissertations. 8250. https://lib.dr.iastate.edu/rtd/8250 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS While the most advanced technology has been used to photograph and reproduce this manuscript, the quality of the reproduction is heavily dependent upon the quality of the material submitted. For example: • Manuscript pages may have indistinct print. In such cases, the best available copy has been filmed. • Manuscripts may not always be complete. In such cases, a note will indicate that it is not possible to obtain missing pages. • Copyrighted material may have been removed from the manuscript. In such cases, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, and charts) are photographed by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each oversize page is also filmed as one exposure and is available, for an additional charge, as a standard 35mm slide or as a 17"x 23" black and white photographic print. -
Cold Flow Performance of a Ramjet Engine
COLD FLOW PERFORMANCE OF A RAMJET ENGINE A Thesis Presented to the Faculty of California Polytechnic State University San Luis Obispo In Partial Fulfillment of the Requirements for the Degree Master of Science in Aerospace Engineering by Harrison G. Sykes December 2014 ©2014 Harrison G. Sykes ALL RIGHTS RESERVED ii COMMITTEE MEMBERSHIP TITLE: Cold Flow Performance of a Ramjet Engine AUTHOR: Harrison G. Sykes DATE SUBMITTED: December 2014 COMMITTEE CHAIR: Eric Mehiel, Ph.D. Associate Professor Aerospace Engineering Department COMMITTEE MEMBER: Patrick Lemieux, Ph.D. Associate Professor, Mechanical Engineering Department COMMITTEE MEMBER: Daniel J. Wait, M.S. Systems Engineer, Tyvak Nano-Satelite Systems LLC iii ABSTRACT Cold Flow Performance of a Ramjet Engine Harrison G. Sykes The design process and construction of the initial modular ramjet attachment to the Cal Poly supersonic wind tunnel is presented. The design of a modular inlet, combustor, and nozzle are studied in depth with the intentions of testing in the modular ramjet. The efforts undertaken to characterize the Cal Poly supersonic wind tunnel and the individual component testing of this attachment are also discussed. The data gathered will be used as a base model for future expansion of the ramjet facility and eventual hot fire testing of the initial components. Modularity of the inlet, combustion chamber, and nozzle will allow for easier modification of the initial design and the designs ability to incorporate clear walls will allow for flow and combustion visualization once the performance of the hot flow ramjet is determined. The testing of the blank ramjet duct resulted in an error of less than 10% from predicted results. -
A Physical Interpretation of Stagnation Pressure and Enthalpy Changes in Unsteady Flow
A Physical Interpretation of Stagnation Pressure and Enthalpy Changes in Unsteady Flow The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Hodson, H. P. et al. “A Physical Interpretation of Stagnation Pressure and Enthalpy Changes in Unsteady Flow.” Journal of Turbomachinery 134, 6 (2012): 060902 © 2012 American Society of Mechanical Engineers As Published http://dx.doi.org/10.1115/1.4007208 Publisher ASME International Version Final published version Citable link http://hdl.handle.net/1721.1/114691 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. A Physical Interpretation H. P. Hodson of Stagnation Pressure T. P. Hynes and Enthalpy Changes Whittle Laboratory, University of Cambridge, in Unsteady Flow 1 JJ Thomson Avenue, Cambridge CB3 0DY, UK This paper provides a physical interpretation of the mechanism of stagnation enthalpy and stagnation pressure changes in turbomachines due to unsteady flow, the agency for E. M. Greitzer all work transfer between a turbomachine and an inviscid fluid. Examples are first given e-mail: [email protected] to illustrate the direct link between the time variation of static pressure seen by a given fluid particle and the rate of change of stagnation enthalpy for that particle. These C. S. Tan include absolute stagnation temperature rises in turbine rotor tip leakage flow, wake transport through downstream blade rows, and effects of wake phasing on compressor e-mail: [email protected] work input. -
CHARACTERISTICS and USE of X-15 AIR-DATA SENSORS by L"Ie D
https://ntrs.nasa.gov/search.jsp?R=19680015845 2020-03-23T22:55:21+00:00Z NASA TECHNICAL NOTE z CHARACTERISTICS AND USE OF X-15 AIR-DATA SENSORS by L"ie D. Webb Flight Research Center Eawards, Cali$ NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. JUNE 1968 TECH LIBWARY KAFB, NM Illllll 11111 lllll Illllllllll lllllIll1Ill CHARACTERISTICS AND USE OF X-15 AIR-DATA SENSORS By Lannie D. Webb Flight Research Center Edwards, Calif. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION For sale by the Clearinghouse for Federal Scientific and Technical Information Springfield, Virginia 22151 - CFSTI price $3.00 CONTENTS SUMMARY ....................................... 1 INTRODUCTION .................................... 1 SYMBOLs ....................................... 2 RADAR AND METEOROLOGICAL SOUNDINGS ................... 4 Radar Measurements ................................ 4 Balloon Soundings .................................. 5 Sounding Rockets .................................. 5 DESCRIPTION OF ONBOARD GUIDANCE SENSORS ................. 6 Nose-Boom Pitot-static Tube ........................... 6 Hypersonic Flow-Direction System (Ball Nose) .................. 7 Pilot's q-Meter ................................... 7 Fuselage Static System ............................... 8 Fuselage Pitot Probe ................................ 8 Stagnation-Temperature Probe ........................... 8 Inertial Flight Data System ............................. 9 RECORDING APPARATUS .............................. 11 DISCUSSION OF CHARACTERISTIC AND CALIBRATION -
Preliminary Design Document ASEN 4018
Preliminary Design Document ASEN 4018 1 of 28 American Institute of Aeronautics and Astronautics Preliminary Design Document ASEN 4018 Contents 2 Project Description 3 2.1 Project Purpose . 3 2.2 Objectives . 3 2.3 CONOPS . 4 2.4 Functional Block Diagram . 5 2.5 Functional Requirements . 6 3 Design Requirements 7 4 Key Design Options Considered 9 4.1 Nozzle Design . 9 4.1.1 de Laval Nozzle . 10 4.1.2 Annular Convergent-Divergent Nozzle (ACD Nozzle) . 10 4.1.3 Variable Geometry Nozzle . 11 4.1.4 Expansion-Deflection Nozzle . 12 4.1.5 Minimum Length Nozzle (MLN) . 13 4.1.6 Heat Transfer for Flow Velocity Control . 13 4.2 Nozzle Testbed . 14 4.2.1 Testing on JetCat Engine vs. Engine Analogue . 14 4.2.2 Hot-flow vs. Cold-flow Testbed . 15 4.2.3 Actual Size vs. Scaled Nozzle . 17 4.3 Nozzle Integration . 18 4.3.1 Complete Nozzle Replacement . 18 4.3.2 Nozzle extension and Overlapping Extension . 19 4.3.3 Nozzle Dome Replacement . 21 5 Trade Study Process and Results 23 5.1 Nozzle Design . 23 5.1.1 Trade Elements . 23 5.1.2 Trade Study . 23 5.2 Nozzle Testbed . 24 5.2.1 Trade Elements . 24 5.2.2 Trade Study . 25 5.3 Nozzle Integration . 25 5.3.1 Trade Elements . 25 5.3.2 Trade Study . 26 6 Selection of Baseline Design 26 6.1 Nozzle Aerodynamics . 26 6.2 Nozzle Test Bed . 27 6.3 Nozzle Integration . 27 2 of 28 American Institute of Aeronautics and Astronautics Preliminary Design Document ASEN 4018 2.