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Shock Tubes Interaction on Meteorites Hypersonic Meteoroid Entry Physics, 61st Course of the International School of Quantum Electronics Ettore Majorana Foundation and Centre for Scientific Culture, 3–8 October 2017, Erice, Italy M. Lino da Silva 1 , A. Smith 2 , A. Chikhaoui 3 , L. Marraffa 4 , R. Rodrigues 1 , M. Castela 1 , R. Gomes 1 , B. Carvalho 1 , L. L. Alves 1 and B. Gon ¸ calves 1 (1): Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa (2): Fluid Gravity Engineering (3): Univesité de Provence (4): European Space Agency, European Science and Technology Center

Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

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Page 1: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock TubesInteraction on Meteorites

Hypersonic Meteoroid Entry Physics,61st Course of the International School of Quantum Electronics

Ettore Majorana Foundation and Centre for Scientific Culture,

3–8 October 2017, Erice, Italy

M. Lino da Silva1, A. Smith2, A. Chikhaoui3, L. Marraffa4, R.Rodrigues1, M. Castela1, R. Gomes1, B. Carvalho1, L. L. Alves1

and B. Goncalves1

(1): Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa

(2): Fluid Gravity Engineering

(3): Univesité de Provence

(4): European Space Agency, European Science and Technology Center

Page 2: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction

Motivation

Meteorites enter Earth’s atmosphere between 11km/s and 72km/s

Shock-Tubes can reproduce the conditions of an atmospheric entry with the highest

degree of physical fidelity. However...Shock-Tubes are impulsive facilities, with a very limited test time (∼ 10−6s)Reaching superorbital speeds is notably difficult from an engineeringstandpoint

Mario Lino da Silva Shock Tubes 4th Oct. 2017 2 / 34

Page 3: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction

Motivation

Meteorites enter Earth’s atmosphere between 11km/s and 72km/s

Shock-Tubes can reproduce the conditions of an atmospheric entry with the highest

degree of physical fidelity. However...Shock-Tubes are impulsive facilities, with a very limited test time (∼ 10−6s)Reaching superorbital speeds is notably difficult from an engineeringstandpoint

Mario Lino da Silva Shock Tubes 4th Oct. 2017 2 / 34

Page 4: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction

Motivation

Meteorites enter Earth’s atmosphere between 11km/s and 72km/s

Shock-Tubes can reproduce the conditions of an atmospheric entry with the highest

degree of physical fidelity. However...Shock-Tubes are impulsive facilities, with a very limited test time (∼ 10−6s)Reaching superorbital speeds is notably difficult from an engineeringstandpoint

Mario Lino da Silva Shock Tubes 4th Oct. 2017 2 / 34

Page 5: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction

Motivation

Meteorites enter Earth’s atmosphere between 11km/s and 72km/s

Shock-Tubes can reproduce the conditions of an atmospheric entry with the highest

degree of physical fidelity. However...Shock-Tubes are impulsive facilities, with a very limited test time (∼ 10−6s)Reaching superorbital speeds is notably difficult from an engineeringstandpoint

Mario Lino da Silva Shock Tubes 4th Oct. 2017 2 / 34

Page 6: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction Outline

Outline of this talk

1 Describe the design strategy for a superorbital shock-tube, including physical modelsand design/engineering approaches

2 Present a sample case-study, outlining its detailed design and choice of technologies3 Discuss the possible configurations for the study of Meteor Entry physics in such

facilities

We will present the ESTHER Shock-Tube as a typical “case-study” facility for the simulationof superorbital, high-speed entries (>11km/s).

Mario Lino da Silva Shock Tubes 4th Oct. 2017 3 / 34

Page 7: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction Outline

Outline of this talk

1 Describe the design strategy for a superorbital shock-tube, including physical modelsand design/engineering approaches

2 Present a sample case-study, outlining its detailed design and choice of technologies3 Discuss the possible configurations for the study of Meteor Entry physics in such

facilities

We will present the ESTHER Shock-Tube as a typical “case-study” facility for the simulationof superorbital, high-speed entries (>11km/s).

Mario Lino da Silva Shock Tubes 4th Oct. 2017 3 / 34

Page 8: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction Outline

Outline of this talk

1 Describe the design strategy for a superorbital shock-tube, including physical modelsand design/engineering approaches

2 Present a sample case-study, outlining its detailed design and choice of technologies3 Discuss the possible configurations for the study of Meteor Entry physics in such

facilities

We will present the ESTHER Shock-Tube as a typical “case-study” facility for the simulationof superorbital, high-speed entries (>11km/s).

Mario Lino da Silva Shock Tubes 4th Oct. 2017 3 / 34

Page 9: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Introduction Outline

Outline of this talk

1 Describe the design strategy for a superorbital shock-tube, including physical modelsand design/engineering approaches

2 Present a sample case-study, outlining its detailed design and choice of technologies3 Discuss the possible configurations for the study of Meteor Entry physics in such

facilities

We will present the ESTHER Shock-Tube as a typical “case-study” facility for the simulationof superorbital, high-speed entries (>11km/s).

Mario Lino da Silva Shock Tubes 4th Oct. 2017 3 / 34

Page 10: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design

Conceptual Design

Requirement driver: reaching high-speed shocks (v>10km/s)

High shock speeds can be reached on a first approach for large driver/test section(HP/LP) ratios. Some practical limitations (p, T, mixture) exist

Some extra performance can be achieved for a variable (A1/A4 >1) area ratiobetween the HP and LP sections (up to 20%)

single-stage variable area shock-tube

Mario Lino da Silva Shock Tubes 4th Oct. 2017 4 / 34

Page 11: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design

Conceptual Design

Requirement driver: reaching high-speed shocks (v>10km/s)

High shock speeds can be reached on a first approach for large driver/test section(HP/LP) ratios. Some practical limitations (p, T, mixture) exist

Some extra performance can be achieved for a variable (A1/A4 >1) area ratiobetween the HP and LP sections (up to 20%)

More significant performance enhancements can only be achieved if we add anintermediary section

two-stage variable area shock-tube

Mario Lino da Silva Shock Tubes 4th Oct. 2017 4 / 34

Page 12: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design

Basic Design Concepts for Maximizing Shock-Tube Performance

1 Thermodynamic design of the driver

2 Shock-Tube cross-section optimization

3 Second stage compression tube optimization

Mario Lino da Silva Shock Tubes 4th Oct. 2017 5 / 34

Page 13: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Thermodynamics of Shock-Tube Driver Design

Thermodynamic Design of the Shock-TubeDriver

Mario Lino da Silva Shock Tubes 4th Oct. 2017 6 / 34

Page 14: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Thermodynamics of Shock-Tube Driver Design

Thermodynamics

Shock-Tube equation

P4P1

=P2P1

1 − (γ4−1) a1a4

(P2P1−1

)√

2γ1

√2γ1+(γ1+1)

(P2P1−1

)−

2γ4γ4−1

Maximization of test section shock speed (a4)for a given initial pressure (P2, imposed), relieson driver parameters: large driver pressure P1,large sound speed V1

s and low γ1

Imposes the selection of a low molecular weigthdriver gas: H2 would be ideal but safety issuesexist, also detrimental effect on γ due to themolecular internal modes

Alternative is using He. Most of Shock-Tubesrely on this gas

Compression of driver gas (piston, combustion, electric arc) increases T, which is beneficial forV1

s . Necessity to compute γ1 values at high p,T

Mario Lino da Silva Shock Tubes 4th Oct. 2017 7 / 34

Page 15: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Variable-Area Shock-Tube Design

Performance of a Variable-Area Shock-Tube

Mario Lino da Silva Shock Tubes 4th Oct. 2017 8 / 34

Page 16: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Variable-Area Shock-Tube Design

Shock Relations for Constant and Variable Area Shock-Tubes (1/2)

Classical Shock-Tube equation for constant area (A4/A1 = 1) is:

P4P1

=P2P1

1 −(γ4 − 1) a1

a4

(P2P1− 1

)√

2γ1

√2γ1 + (γ1 + 1)

(P2P1− 1

)−

2γ4γ4−1

(1)

For variable area (A4/A1 , 1) we consider the Alpher and White1 approach, considering an “equivalence” factor g asdefined by Resler 2 .

For a variable area:

A4A1

=MeM3a

2 + (γ4 − 1)M23a

2 + (γ4 − 1)M2e

γ4+1

2(γ4−1

)(2)

Since we are in the supersonic case, we have Me = 1. We may then determine M3a iteratively.

We then solve for the “equivalence” factor g as defined from Resler:

g =

√√

2 + (γ4 − 1)M23a

2 + (γ4 − 1)M2e

[2 + (γ4 − 1)Me2 + (γ4 − 1)M3a

]2γ4γ4−1

(3)

Mario Lino da Silva Shock Tubes 4th Oct. 2017 9 / 34

Page 17: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Variable-Area Shock-Tube Design

Shock Relations for Constant and Variable Area Shock-Tubes (2/2)

We can then use the modified Shock-Tube equation for a variable area ratio:

P4P1

=P2P1

g−1

1 − u2a1

a1a4

γ4 − 12

g−γ4−12γ4

2γ4γ4−1

(4)

where we have:

a1u2

=γ1 + 1

2Ms

M2s − 1

(5)

with the shock-speed Ms defined as a function of P2/P1

Ms =

√γ1 − 1

2γ1

(1 +

γ1 + 1γ1 − 1

P2P1

); (6)

We may finally solve solve the variable area Shock-Tube equation (Eq. 4) iteratively in a similar fashion to the constantarea Shock-Tube equation (Eq. 1).

Mario Lino da Silva Shock Tubes 4th Oct. 2017 10 / 34

Page 18: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Two-Stage Shock-Tube Design

Performance of a Two-stage Shock-Tube

Mario Lino da Silva Shock Tubes 4th Oct. 2017 11 / 34

Page 19: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Two-Stage Shock-Tube Design

Shock Diagram for a Two-Stage Shock-Tube

Two-stage configurations allow for higher shock speeds at the cost of decreasedrun-times (due to faster contact waves)

Optimization parameters for second stage: Gas composition (always He andpressure p)

Mario Lino da Silva Shock Tubes 4th Oct. 2017 12 / 34

Page 20: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Application to the ESTHER Shock-Tube Design

A few examples: Application to the design ofthe ESTHER Shock-Tube

Mario Lino da Silva Shock Tubes 4th Oct. 2017 13 / 34

Page 21: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Application to the ESTHER Shock-Tube Design

Optimized Two-Stage Shock-TubeShock velocity dependence on driver pressure

Variable driver pressures from 100 to600bar

Test section for different planetaryconditions (Earth, Mars entry)

Increasing the driver pressure up to600bar yields 2–2.3km/s increase inshock velocity

Test gas pressure can be decreased

below 10Pa but of little relevance:

Too rarefied regime, outsidepeak fluxes regionCollected radiation will beminimal due to the low density

Mario Lino da Silva Shock Tubes 4th Oct. 2017 14 / 34

Page 22: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Application to the ESTHER Shock-Tube Design

Optimized Two-Stage Shock-TubeShock velocity dependence on area ratio

Up to +1km/s can be achieved through avariable area driver/driven section. Needsoptimized diaphragm design

Diminishing returns as the area ratioincreases

Optimization becomes an engineering

problem: How large of a driver can you

afford as a price for extra performance?

Increased material mass, larger wallstresses due to increased diameterMore costs per shot, need to filllarger volumes of driver gas (He isexpensive)Safety issues with large vesselsunder extreme pressures

Mario Lino da Silva Shock Tubes 4th Oct. 2017 15 / 34

Page 23: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Shock-Tube Design Application to the ESTHER Shock-Tube Design

Optimized Two-Stage Shock-TubeTest times calculations

In ideal case, shock goes faster than contact wave, therefore test time increases withdistance of the test section to the diaphragm (see previous slide)

Shock in fact slows down as it progresses and contact wave accelerates untildistance between both reaches a constant value. Boundary layer acts as a mass sinkbetween shock and contact surface

Analysis by Mirels

⇒ H. Mirels, “Test-time in Low-Pressure Shock-Tubes”, Phys. Fluids, Vol. 6, No. 9, Sep. 1963)

Mario Lino da Silva Shock Tubes 4th Oct. 2017 16 / 34

Page 24: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

Case Study: The new European shock-tube forsuperorbital entries kinetics and radiation:

The ESTHER Shock-Tube

Mario Lino da Silva Shock Tubes 4th Oct. 2017 17 / 34

Page 25: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

Overview of ESA’s European Shock-Tube for High Enthalpy Research

Facility developed by an international consortium led by the IST of Lisbon, underfunding from the European Space Agency. Support to future European planetaryexploration missionsTwo-Stage combustion-driven (He/H2/O2 mixture) shock-tube. Laser ignition (1st

facility of its kind)High Pressure (HP) section: 60–600+bar, Mid Pressure (MP) section: 0.1–0.5bar,Low Pressure (LP) section: 10–0.1mbarVariable area cross-section: HP: 200mm∅, MP: 130mm∅, LP: 80mm∅Hydraulics system for sections closureBraking system ensures adequate shock-tube stiffnessPrimary and turbomolecular pump system for ensuring vacuum down to 10−6 mbar inthe test section.

Mario Lino da Silva Shock Tubes 4th Oct. 2017 18 / 34

Page 26: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

ESTHER Consortium

Mario Lino da Silva Shock Tubes 4th Oct. 2017 19 / 34

Page 27: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

Shock-Tube FacilitiesA World outlook

o

ESTHER is a World-class facility

Mario Lino da Silva Shock Tubes 4th Oct. 2017 20 / 34

Page 28: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

Technological OptionsA comparison of different shock-tube facilities

Driver section technology

Strong recoil Pollution Repeatability PerformanceMoving parts risks in the Driver (high p, T)

Piston (X2, X3) yes no good moderateElectric Arc (NASA EAST) no yes bad excellentComb. Detonation (TH2) no yes moderate / bad excellentComb. Deflagration (ESTHER, VUT-1) no no / yes good good

Test section material

Surface pollution Leakage risks fromfrom Carbon Al2O3 flaking

at the window interfaces

Aluminium (EAST, HVST, X2, X3) no yesSteel (VUT-1) yes noLow-carbon Steel (ESTHER) needs good no

vacuum cleaning

Mario Lino da Silva Shock Tubes 4th Oct. 2017 21 / 34

Page 29: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

Laser-Ignition DriverA World first

Scaled combustion chamber installed forproof-of-concept

First configuration included an axialconstantan hotwire for radial ignition

Issues related to wire pollution andbreakage of ceramic insulators in case ofdetonation

We successfully applied a laser ignitionsystem to the bombe

No parts inside the driver, no pollution fromwire residues

Very good repeatability reached with nodetonations. Maximum pressure: 610bar: Aworld record for laser ignition

Ignition threshold: 108W/cm2 forp>20–30bar. Two orders of magnitudebelow minimum ignition values from theliterature. Effect of impurities/dust?Mario Lino da Silva Shock Tubes 4th Oct. 2017 22 / 34

Page 30: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

The Challenge of a Lifetime

Mario Lino da Silva Shock Tubes 4th Oct. 2017 23 / 34

Page 31: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

ESTHER Case-Study

The Challenge of a LifetimeCurrent Status: Bench assembled and aligned

Mario Lino da Silva Shock Tubes 4th Oct. 2017 24 / 34

Page 32: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Meteroroid Entry Physics Studies

Ablation Studies in Impulsive Facilities

A Few Examples

Mario Lino da Silva Shock Tubes 4th Oct. 2017 25 / 34

Page 33: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Meteroroid Entry Physics Studies

Ablation Studies in Shock-Tube FacilitiesCase-Studies from the University of Queensland

University of Queensland (Australia) operates several superorbitalshock-tube facilities in wind-tunnel mode (X2, X3)

UQ has been pioneering Ablation studies in such facilities, demonstratingthe viability of impulsive facilities for materials testing

We will discuss a few recent experiments that are highly relevant for meteorentry physics

Mario Lino da Silva Shock Tubes 4th Oct. 2017 26 / 34

Page 34: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Meteroroid Entry Physics Studies

Experimental setup for the X2 Expansion Tube

Expansion shock-tube X2

Diagnostics setup includes a fast iCCDcamera and a VUV-capable spectrograph

S. W. Lewis et al. “Expansion Tunnel Experiments of Earth Reentry Flow with Surface Ablation”,

J. Spacecraft Rockets, Vol. 53, 2016, pp. 887–899. T. N. Eichmann, “Radiation measurements in a simulated Mars atmosphere”,

PhD Thesis, University of Queensland, 2012.

Mario Lino da Silva Shock Tubes 4th Oct. 2017 27 / 34

Page 35: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Meteroroid Entry Physics Studies

Heat-Fluxes at Stagnation PointAnalytical estimates and spectra from epoxy coating ablation on the X2 expansion tube

Stagnation heat-flux approximation from Zobya

qs = Ki

√ρu2 u2√reff

Shultz and Jonesb T change for constant heat flux

∆Ts = 2qs√π

√tρck

and 10%, 1% step function thermal pulse penetration depth

x = 2x∗√αt

x = 0.3√

t

Experiment from D’Souza, showing ablation of an epoxy coatingover a model: ∆T=178K with 10% T penetration depth of 6µm in50µs.

aE. Zoby, “Empirical Stagnation-Point Heat-Transfer Relationin Several Gas Mixtures at High Enthalpy Levels,” NASA TND-4799, 1968.

bD. L. Schultz, and T. V. Jones, “Heat-Transfer Measurementsin Short-Duration Hypersonic Facilities,” AGARD AGARDographAG–165, 1973.

M. G. D’Soza et al., “Observation of an Ablating Surface in Expansion Tunnel Flow ”,

AIAA Journal,Vol. 48, No. 7, 2010, pp. 1557–1561.

Mario Lino da Silva Shock Tubes 4th Oct. 2017 28 / 34

Page 36: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Meteroroid Entry Physics Studies

Ablation of a Preheated Carbon StructureExperiment in the X2 expansion shock-tunnel

Preheating of a carbon sample toT=2000K, using a copper resistance

Spectral measurements in the near-VUV(350–390nm) and high-spedd imaging byiCCD camera

Excess C and CN radiation measured inthe flow. Ablation products observed by anICCD camera (see figure below, detail A)

F. Zander et al. “Hot-Wall Reentry Testing in Hypersonic Impulse Facilities”,

AIAA Journal, Vol. 51, No. 2, 2013, pp. 476–484.

F. Zander et al. “Hot-Wall Reentry Testing in Hypersonic Impulse Facilities”, AIAA Journal, Vol. 51, No. 2, 2013, pp. 476–484.

Mario Lino da Silva Shock Tubes 4th Oct. 2017 29 / 34

Page 37: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Meteroroid Entry Physics Studies

Frozen Post-Shock FlowsWedge insertion in a shock-tunnel flow (X2 and EAST)

Sangdi Gu et al., “Study of the Afterbody Radiation during Mars Entry in an Expansion Tube”, AIAA paper 2017–0212, 2017

Comparison between experimental data using iCCD cameras and CFD simulations

Sangdi showed (in Mars entry conditions) that inserting a wedge leads to thefreezing of the flow behind the oblique shock

More investigations needed, but this could relevant for meteor wake radiationreproduction

Mario Lino da Silva Shock Tubes 4th Oct. 2017 30 / 34

Page 38: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Conclusions

Conclusions

Mario Lino da Silva Shock Tubes 4th Oct. 2017 31 / 34

Page 39: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Conclusions

Conclusions

Shock-Tubes are at the performance limit for meteor studies. Facilitiesranging from 11–14km/s should nevertheless suffice for understanding theµ of meteor entry thermophysics

They provide the most realistic conditions of an atmospheric entry but thelimited test run times (a few 10’s of µs) constitute significant challenges

VUV radiation is key owing to the superorbital entry regime⇒ Furtherchallenges related to the deployment of VUV rated diagnostics

Mario Lino da Silva Shock Tubes 4th Oct. 2017 32 / 34

Page 40: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Conclusions

In memory of Prof. Michel Dudeck (1945–2017)

Mario Lino da Silva Shock Tubes 4th Oct. 2017 33 / 34

Page 41: Shock Tubes 0.2cm Interaction on Meteorites · Test times calculations In ideal case, shock goes faster than contact wave, therefore test time increases with distance of the test

Mario Lino da Silva Shock Tubes 4th Oct. 2017 34 / 34