Instructional Design Document Shock Wave STAM Interactive Solutions

Demo Outline (For reference) ‏ Topic NumberTopic NamePage Type 1NozzleAnimated page 2Internal Flow Pattern in a NozzleInteractive page 3External Flow PatternAnimated page

Slide 14Change the narration to: ‘As the approaching shock wave hits the wedge, it undergoes reflection and diffraction’ 7 Changes Suggested by Prof. PuranikChanges reflected on slide no. 1Start with definition of shock, voice over to say that internal and external shock will be discussed in this animation Slide 4 2Include shocks may be stationary as well.Slide 4 3Show current (Nasa style) animation / interactivity for external flow – add color to indicate temperature qualitatively. Replace “shock” with approaching flow, keep wedge stationary Slide 13 4Introduce parameters of convergent-divergent nozzles (shape, throat, P1 and P2 Show images – flow velocity and location of shock Slides Add textbooks as suggestedSlide 15 6Modify quiz question 1 - Change language to say “across” the shock wave Modify quiz question 2 -Correct answer is 1, not 2, Reframe as marked and show downstream/upstream on figure Slides 16 & 17 Change Log (as per the minutes pdf) ‏

Shock Wave Fundamentals of Gas Dynamics A shock wave is a disturbance that propagates through a medium. While the shock-wave usually travels through the medium, standing or stationary shock waves can occur in some circumstances in both liquids and gases. Mach number describes the type of flow. This demo illustrates both internal and external flow patterns.

Shock Wave Fundamentals of Gas Dynamics Nozzle Converging Diverging Nozzle A nozzle is often used to control the speed of flow.

Shock Wave Fundamentals of Gas Dynamics Internal Flow Pattern in a Nozzle Back Pressure (Pb): Vary the back pressure to see the flow pattern.

Shock Wave Fundamentals of Gas Dynamics Reference slide for default value The flow through the nozzle is completely subsonic.

Shock Wave Fundamentals of Gas Dynamics Reference slide if the back pressure is reduced by one step The flow pattern is exactly the same as in subsonic flow, except that the flow speed at the throat has just reached Mach 1.

Shock Wave Fundamentals of Gas Dynamics Reference slide if the back pressure is further reduced by one step A region of supersonic flow forms just downstream of the throat.

Shock Wave Fundamentals of Gas Dynamics Reference slide if the back pressure is further reduced by one step The supersonic region extends all the way down the nozzle until the shock is sitting at the nozzle exit.

Shock Wave Fundamentals of Gas Dynamics Reference slide if the back pressure is further reduced by one step Shock bends out into the jet, and a complex pattern of shocks and reflections is set up in the jet which will now involve a mixture of subsonic and supersonic flow, or just supersonic flow.

Shock Wave Fundamentals of Gas Dynamics Reference slide if the back pressure is further reduced by one step Waves in the jet disappear altogether, and the jet will be uniformly supersonic.

Shock Wave Fundamentals of Gas Dynamics Reference slide if the back pressure is further reduced by one step Expansion waves form at the nozzle exit.

Shock Wave Fundamentals of Gas Dynamics External Flow Pattern Wedge (Object) ‏ Approaching Shock Wave

Shock Wave Fundamentals of Gas Dynamics Resources Books: J.D. Anderson, Modern Compressible Flow with Historical Perspective, 3 rd Edition, McGraw-Hill, H.W. Liepmann and A. Roshko, Elements of Gas Dynamics, Dover Publications, Reference Links:

Shock Wave Fundamentals of Gas Dynamics The velocity, temperature and pressure across the shock wave are characterized by Euler's Equation Bernoulli's Equation Navier-Stokes Equation Rankine-Hugoniot Equation

Shock Wave Fundamentals of Gas Dynamics Downstream of the shock wave Pressure and Temperature are lower Pressure and Temperature are higher Pressure is higher but Temperature is lower Pressure is lower but Temperature is higher This image will be enhanced visually

Shock Wave Fundamentals of Gas Dynamics Which best describes the shock wave-front? All thermodynamic properties of the medium change gradually All thermodynamic properties of the medium change instantaneously All thermodynamic properties of the medium change almost instantaneously Some thermodynamic properties of the medium change gradually, some instantaneously

Shock Wave Fundamentals of Gas Dynamics The strength of a shock can be measured by the ratio of downstream to upstream pressures. As the Mach number increases the strength of the shock wave decreases the strength of the shock wave increases depends on the medium of propagation depends on the initial pressure in the medium

Shock Wave Fundamentals of Gas Dynamics Shock waves can be caused by cavitations caused by the collapse of a bubble objects such as bullets or planes flying faster than sound explosions in gaseous media objects such as bullets or planes flying at a speed less than sound