1 Workshop has been s cheduled for - PowerPoint Presentation

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1 Workshop has been s cheduled for - PPT Presentation

Jan 2 3pm6 pm Jan 3 8am6pm Shown in the current Aerospace America Telecon agenda A ugust 6 2015 Review July telecon notes Action items amp issues Administrivia Dates Website ID: 799665

telecon time results psd time telecon psd results analysis data thist function frequency nfft response junk amp aepw nasa

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Slide1

Workshop has been

cheduled for

Jan 2 (3pm-6 pm)

Jan 3 (8am-6pm)

Shown in the current

Aerospace America

Slide2

Telecon

agenda, August 6, 2015

Review July

telecon notesAction items & issuesAdministrivia

Dates

Website

AIAA coordinationOther happeningsResults discussionPost processing topicsFrequency response function calculationsPhase definitionDamping calculation (loss factor)Next telecon Sept 3, 11 a.m.

Slide3

Important Dates

Computational Results Submitted by

Nov 15, 2015

Workshop: SciTech 2016:

Jan

2-3, 2016

Computational Team Telecons: 1st Thursday of every calendar month 11 a.m. EST

Slide4

July

telecon

summary

Held on July 2, 2015 11 a.m.Next telecon August 6, 11 a.m. East Coast time in U.S.

Administrative matters

Telecon

slides now uploaded to websiteDeadline established for declaring participation as an analysis team: Oct 1Advertisement blurb submitted to AIAA Analysis resultsKrishna Zore from ANSYS shared results- phase difference relative to experimental data noted; may be definition Jennifer Heeg showed unforced unsteady results for Case 3 (Mach 0.85, 5°); Shock motion of ~9% of the chord for the unforced (no excitation) system is very similar using:EZNSS hybrid DDES (based on k-w SST) , shown by Daniella Raveh on June telecon

FUN3D RANS + SA

FUN3D URANS + SA

Daniella Raveh from

Technion

showed results on the June telecon for Case 3: EZNSS RANS solutions showed dependence on the turbulence modelConsistent turbulence model study added to the analysis matrix: Case 2: Flutter at Mach 0.74, 0° angle of attack. For those running RANS analysis, utilize your code’s standard Spalart-Allmaras turbulence modelDiscussed the format and content of the panel discussion for SciTech

Slide5

July actions and issues

Embraer personnel had a problem downloading one of the fine meshes. (

Pawel

to work this)Generate postings to websiteAdvertising blurbJuly telecon slides

Off-line examination of ANSYS FRF’s

Administrative support for workshop: email NESC with request

Slide6

August action items and issues

AIAA Structural Dynamics Technical Committee meeting is Monday August 10. They have requested a brief set of charts on workshop status.

Generate slides (Jen)

Is anyone from the analysis teams attending that meeting? Willing/eager to present the material?Analysis matrix email (Pawel Chwalowski)

S-A implementation; Turbulence model website (

Pawel

Chwalowski)Lift and pitching moment coefficient comparison for Test Case 1 (Mach 0.7, 3 degs)6

Slide7

Analysis

Team

Code

POCs

contact

Technion

- IIT

EZNSS

Daniella Raveh

daniella@technion.ac.il

FOI

EDGE

Adam

Jirasek, Mats Dalenbring

adam.jirasek@gmail.com

NASA

SU2

Dave SchusterDavid.m.Schuster@nasa.govNASAFUN3DPawel Chwalowski, Jennifer HeegPawel.Chwalowski@nasa.gov, Jennifer.heeg@nasa.govBrno University of Technology, Institute of Aerospace Engineering Czech RepublicEDGEJan Navratilnavratil@fme.vutbr.czNLRBimo Pranatabimo.prananta@nlr.nlNLRNASTRANBimo Pranatabimo.prananta@nlr.nlIndian Institute of ScienceFLUENTkartik venkatramankartik@aero.iisc.ernet.inIstanbul Technical UniversitySU2Melike Nikbay'nikbay@itu.edu.trATA EngineeringLowPsiChemEric Bladeseric.blades@ata-e.comEmbraer S.A.CFD++,ZTRAN, NASTRAN *Guilherme Ribeiro Begniniguilherme.benini@embraer.com.brPolitechnico di MilanoVarious codesSergio Riccisergio.ricci@polimi.itAFRLFUN3DRick GravesRick.Graves@us.af.milMississippi StateMASTManav BhatiaBhatia@ae.msstate.eduZurich University of Applied Sciences (ZHAW, ZUAS)EDGE, SU2Marcello Righirigm@zhaw.chGeneral Atomics Aeronautical SystemsFLUENT/ANSYSAskar Konkachbaev askar.konkachbaev@ga.comANSYSANSYS Fluent, ANSYS CFX, ANSYS MechanicalBalasubramanyam Sasanapuri(Krishna Zore, Thorsten Hansen, Michael Tooley, Eric Bish)balasubramanyam.sasanapuri@ansys.comUniversity of StrasbourgYannick Hoarau (Jan Vos)Hoarau hoarau@unistra.fr

AePW-2 Analyses/Commitments to date (5/29/2015)

Matrix will be emailed to all listed POC’s to ask their status on analyzing each test case

Slide8

Potential

venues to present results & hold special

sessions for AePW-2

AIAA Aviation Conference: June 2016 (abstracts due ~ Nov 1, 2016)NATO AVT-246 specialists meeting: Sept 2016 (abstracts due Oct 1, 2015) AIAA

SciTech: Jan

2017 (abstracts due ~ June 1, 2016)

International Forum on Aeroelasticity & Structural Dynamics, 2017 Lake Como: June 2017 (abstracts due ~ Dec 1, 2016)8

Slide9

Preliminary Meeting Announcement

and

CALL FOR PAPERS

for the

AVT-246 Specialists’ Meeting (RSM)

Progress and Challenges in Validation Testing for Computational Fluid DynamicsOrganized by the Members of theAPPLIED VEHICLE TECHNOLOGY PANEL (AVT) AVT-246to be held in Zaragoza, Spain 26-28 September 2016Contributions and participation are invited from NATO Nations, Australia and Sweden onlyFinal Deadline for submission of abstracts is 1 October 2015

Slide10

Analysis

Team

Code

POCs

contact

Technion

- IIT

EZNSS

Daniella Raveh

daniella@technion.ac.il

FOI

EDGE

Adam

Jirasek, Mats Dalenbring

adam.jirasek@gmail.com

NASA

SU2

AePW-2 Analyses/Commitments to date (5/29/2015)

Slide11

Analysis team map

Slide12

Telecon

agenda, August 6, 2015

Review July

telecon notesAction items & issuesAdministrivia

Dates

Website

AIAA coordinationOther happeningsResults discussionPost processing topicsFrequency response function calculationsDamping calculation (loss factor)Next telecon Sept 3, 11 a.m

Slide13

Frequency response function estimates using

fourier analysis

references:Oppenheim & Shafer,

Discrete-time signal processingJay Hardin, NASA RP-1145, Introduction to time series analysisBendat & Pierson, Engineering applications of correlation and spectral analysis

Slide14

Frequency response functions (FRFs) magnitude calculation example

Here,

x = pitch angle

y = Cp

1 FRF for each pressure transducer or grid point

Frequency, Hz

Magnitude of FRF,

Pressure / excitation: At frequencies where there is no excitation, the calculation is dividing by 0’ish numbers, making the FRF a large amplitude noisy response

Slide15

Frequency response functions (FRFs) magnitude calculation example

Here,

x = pitch angle

y = Cp

1 FRF for each pressure transducer or grid point

Examine values only at the

excitation frequency

Frequency, Hz

Excitation frequency , in this example, ~80 HzMagnitude of FRF, Cp/

Slide16

Frequency response functions (FRFs) magnitude calculation example

Here,

x = pitch angle

y = Cp

1 FRF for each pressure transducer or grid point

Examine values only at the

excitation frequency

Plot the results for all transducers on a single

plot, as a function of chord location

Frequency, Hz

Excitation frequency ~ 80 HzMagnitude of FRF, Cp/

Magnitude of FRF,

x/c

Evaluated at the excitation frequency ~ 80 Hz

Slide17

Frequency response function estimates using Fourier analysis

FRF

y,x

frequency response function estimate for response y due to input x

PSD

Power spectral density function estimate for a time history xCSDy,x(f): Cross spectral density function estimate for a response y due to an input xMSCoherey,x(f): or g2y,x(f): mean squared coherence estimate for a response y due to an input xFFTx(f): discrete Fourier transform of time history x, at frequencies f. Time history x has length nfft samples and a sample rate of samp.f: frequency, Hzk: integer index of frequencysamp: number of samples per second = (1/time step size)nfft: number of samples (points in time) in the data record (time history) being analyzed by the Fourier transform Note that this will be the block size or the periodogram length when the

periodogram

(block averaging) method is employed

Slide18

Frequency response function estimates using Fourier analysis

Slide19

Discrete Fourier Transform

Slide20

Code snippets

[Pxx_1,

frsw, junk, junk, junk,junk

periodogram_jh_v4(thist_in,thist_in,nfft_1,N_overlap_1,str_win,samp,0

); [Pyy_1, frsw, junk, junk, junk,junk]=periodogram_jh_v4(thist_out,thist_out,nfft_1,N_overlap_1,str_win,samp,0); [Pxy_1, frsw, junk, junk, junk,junk]=periodogram_jh_v4(thist_in,thist_out,nfft_1,N_overlap_1,str_win,samp,0); Txy_1=Pxy_1 ./ Pxx_1;

Cxy_1 = (abs(Pxy_1).^2)./(Pxx_1.*Pyy_1);

_______________________________________________________________________________________________

function [Pxy, freq_axis, fft_x_amplitude, fft_y_amplitude, N_blocks, Save_data]=periodogram_jh_v4(thist_x,thist_y,nfft_1,N_overlap_1,str_win,samp,flag_amplitudes)freq_axis=(samp/(nfft_1))*[0:(nfft_1-1)];for iii=1:N_blocks; ibeg=(iii-1)*(nfft_1-N_overlap_1) + 1;

iend

=ibeg+nfft_1-1;

Detrending

added for each segment for experimental data. This is

% not in the CFD processing thist_xa=detrend(thist_x(ibeg:iend),'constant'); thist_ya=detrend(thist_y(ibeg:iend),'constant'); thist_xwin=win_1 .* thist_xa; thist_ywin=win_1 .* thist_ya; fftx_1a=fft(thist_xwin); ffty_1a=fft(thist_ywin); %%%Pxy_1a=2*(fftx_1a .* conj(ffty_1a))/ nfft_1 / samp; Pxy_1a=2*(ffty_1a .* conj(fftx_1a))/ nfft_1 / samp; Pxy_sum=Pxy_sum + Pxy_1a;end;Pxy=Pxy_sum / N_blocks;NOTE: In the coding, the meaning of the x and y variables areREVERSED relative to the derivations on the previous slides!!!!% thist_x is numerator quantity time history (i.e. the sensor in an FRF)% thist_y is the denominator quantity time history (i.e. the actuator in an FRF)

Slide21

Correcting for windowing- Needed if you are comparing PSDs or CSDs instead of FRFs

(JH function

correct_PSD_for_window.m

)

Pxx_in Given the PSD computed the usual Jen normalizations:%%

PSD_junk

fft_x

conj(fft_x)) / (nfft)/samp;% PSD_in= [PSD_junk(1); 2*PSD_junk(2:end-1) ; PSD_junk

(end)];

% win1 is the time history (Impulse response function) of the window

nfft

is the time history length, or the Fourier analysis block length

%% samp is the sample rate in samples/second = 1/ delta_tfunction [PSD_corrected,PSD_scaled,Sine_amp]=correct_PSD_for_window(Pxx_in,win1,nfft,samp);% PSD_scaled:% Normalizing by NPG_jh will give the same answer for the PSD as returned by the% pwelch function and the cpsd calculation. i.e. the _scaled values of% the PSD are equivalent to those produced by pwelch and cpsd. These% values represent the PSD values normalized by the Noise Power Gain.%% PSD_corrected:% In order to remove the magnitude scaling effect of the window from the% PSD, it is required that the scaled PSD be multipled by the Equivalent% Noise BandWidth.%% or, all of this normalization can be done in 1 step. See the equation% for PSD_manual_Equiv_to_unwindowed_check.% % Sine_amp is the amplitude of the sinusoidal time history, calculated% from the PSD results

Slide22

Correcting for windowing - Needed

if you are comparing PSDs or CSDs instead of

FRFs

(JH function correct_PSD_for_window.m

)

norm_win1=sum (win1 .* win1) ^(1/2);NPG_jh=norm_win1^2/nfft;

PSD_scaled

= (1/

NPG_jh

) *

Pxx_in; Window_norm=norm(win1); % to normalize such that the PSD produced by a windowed time history is% the same as that produced by the orignal sine wave time history,% multiply by ENBW (equivalent noise band width)ENBW = nfft*sum(win1 .* win1 ) / sum(win1)^2;

PSD_corrected

PSD_scaled

* ENBW;

function

[

PSD_corrected,PSD_scaled,Sine_amp

]=correct_PSD_for_window(Pxx_in,win1,nfft,samp);

Slide23

Telecon

agenda, August 6, 2015

Review July

telecon notesAction items & issuesAdministrivia

Dates

Website

AIAA coordinationOther happeningsResults discussionPost processing topicsFrequency response function calculationsDamping calculation (loss factor)Next telecon Sept 3, 11 a.m

Slide24

Damping calculation using logarithmic decrement with moving block technique

This isn’t the only method to determine the modal damping.

It is based on the assumption of a single degree of freedom with damped harmonic oscillation.

Damping should ideally be calculated using the pitch angle.The method can be used on the generalized displacement results, but note that for cases with any significant amount of dynamic pressure, the modes are coupled. They have to be combined to represent a physical quantity.

Slide25

Logarithmic Decrement applied to AePW-2 analysis results: Outline of method

Compute pitch angle

Subset the data by user-interactive data points for beginning and end points

Remove the meanDetermine zero crossingsInterpolate to find improved detrending parametersUtilize the absolute value of the

detrended

time history

Take logarithm of peak values for each ½ cycle blockPerform Least squares fit to the datadamping=-1*Linear term coefficient / Mean_freq_rad;25

Slide26

Slide27

Slide28

Slide29

Slide30

Slide31

Slide32

General material and prior

telecon summaries

Slide33

Updated analysis parameter table

Slide34

June

telecon

summary

Held on June 11, 2015 11 a.m.Next telecon July 2, 11 a.m. East Coast time in U.S.

Administrative matters

Analysis team matrix updates continue

Introduced SciTech panel discussionAnalysis resultsMarcello Righi, Zurich University of Applied Sciences (ZHAW, ZUAS) Case 1: showed results using Edge and SU2Unforced system shown as both average results from dynamic case and steady analysisFrequency response functions at forcing frequency & at higher harmonics; showed disagreement in the shock/divot regionDaniella Raveh, Technion: Cases 2: Varied time step size, temporal convergence criteria and turbulence model

Flutter frequency was slightly lower with a finer mesh;

temporal convergence study showed increased damping with decreased time step size; “good enough” declared at time step size of 0.00024

seconds

turbulence model changed

the dampingSolution hasn’t converged to an oscillatory behavior at 1.5 seconds (~ 6 cycles); more iterations (global time steps) are neededCase 3: hybrid DDES shows unsteady flow with shock motion34

Slide35

May

telecon

summary

Held on May 7, 2015 11 a.m.Next telecon June 11, 11 a.m. East Coast time in U.S.

Discussed administrative matters

AIAA coordination: Workshop will be held Saturday Jan 2 (3pm-6pm) & Sunday Jan 3 (8am-6pm)

Workshop processWorkshop agendaDiscussed having a panel / discussion session at SciTech- during the conference weekAnalysis team matrix updates continueSuggested face to face at AIAA Aviation conference- not a lot of anticipated participationCorrected & updated workshop information from MayUnits on stiffness valuesKh = 2637 lb/ft = 219.75 lb/in = 219.75

slinch

/sec^2

Ktheta

= 2964 ft-lb/rad = 35568 in-

lb/rad= 35568 slinch-in^2/s^2/radCorrected Reynolds number for Case 1 (Mach 0.7, 3°)Rec = 4.56x106; Re = 3.456x10635

Slide36

AIAA Interactions

Approved and signed off by

Bruce Willis, Chairman of Structural Dynamics Technical Committee

Megan Scheidt, Managing Director of Products and Programs

Slide37

Envisioned Workshop Process

for Analysis Teams (May, 2015)

Perform analyses

Submit results Prepare informal presentations for workshopSciTech 2016AePW-2

Present results

Results comparisons

Discussion of resultsPath forwardPanel discussion???Re-analyzePublish at special sessions of conferences (which conferences?)Publish combined journal articles37

Slide38

AePW-2 Agenda Thoughts

Incorporate fresh perspectives in how we organize the workshop

Following past workshops:Introductory material

Welcome & overviewExperimental data setGeometry & grid system overviewParticipant presentations

Workshop data summary & discussion

Path forward, re-analysis discussions

Propose a roundtable discussion (1 hour? 2 hours?) for the SciTech conference a few days after the workshopBrief overview of the activitySummary of the data comparisonsPanel containing willing and eager analysis team members38

Slide39

April

telecon

summary

Held on April 2, 2015 11 a.m.Next telecon May 7, 11 a.m. East Coast time in U.S.Updated analysis parameters matrix; uploaded to website

Experimental data was added to website

List of analysis teams produced

Discussion of workshop datesExperimental data reduction showing “divot” in the FRFs to likely be physicalPawel showed animation of flutter solution at Mach 0.74 using FUN3D39

Slide40

March

telecon

summary

Website address: http://nescacademy.nasa.gov/workshops/AePW2/public/Held on March 12, rather than March 5 (with the usual March daylight savings time issues)

telecon

April 2, 11 a.m. East Coast time in U.S.SU-2 doesn’t have existing FSI capability.(Melike and Dave Schuster to talk about this?)Block-structured grids from AePW-1 are available, generated by Thorsten Hansen at ANSYS. (Thorsten and Pawel will work together to make those available on the new website.)The molecular weight of R-134a isn’t the same as a standard property table shows (102 g/mol). The value derived using the listed properties is more like 98 g/mol. This is due to the practical issue of gas purity that is achieved in the wind tunnel. The values on the table are from the test data, where the purity was likely 95%’ish. (Pawel will add a line for molecular weight to the analysis parameters table.)Add the following to the table of analyses:ATA Engineering (Eric Blades will run LoPsiChem

)

AFRL (Rick Graves will run FUN3D)

Milano

Polytechnico

(Sergio Ricci will run numerous codes)Please send comments regarding the distributed slides. In particular, are you okay with the abstract submittal form? With regard to submitting data to the workshop for comparison:Can you provide results in matlab?How do you feel about providing them in a data structure in matlab? Doublet lattice aeroelastic solution results:Bimo and Jen will work to present the results to date at the next teleconWe will put the bulk data file, including the aero model and the flutter cards on the web site. This can serve as a basis for those who might want to use correction methods, etc.Temporal convergence resultsOrganizations may not have the resources to perform the temporal convergence study for all grids. It is suggested that this be done for a grid resolution where things look to be spatially converged. Experience at NASA has shown qualitatively different results for the unstructured coarse grid than those observed for the finer grid resolutions. The flutter results at low Mach number (Mach 0.74) have shown great variation with regard to time step size. The predicted aeroelasticity stability of the system has been shown to be a function of the time step size and the subiteration convergence level. 40

Slide41

March

telecon

summary

Website address: http://nescacademy.nasa.gov/workshops/AePW2/public/Held on March 12, rather than March 5 (with the usual March daylight savings time issues)

telecon

)

AFRL (Rick Graves will run FUN3D)

Milano

Polytechnico

Slide42

Feb

Telecon

Notes

Attendees list (to be added)Suggested adding to website:Participating teams and matrix with contact informationExperimental data (Action item taken by Jen.)

Request made that the frequency response function information be available in both rectangular form (Re and

components) as well as in polar (Mag and phase) form. (Action item taken by Jen.)Experimental results for Case 1. In the FRF magnitude, there is a sawtooth near the leading edge. What is the source of that? Physical? Sensor issue? (Action item taken by Jen.)Grids: structured grids were generated by NASA in plot3D format using Pointwise. The gridding guidelines still include the RSW and HIRENASD from AePW-1. Need to revise them so that they are not confusing. Revisit them also with regard to the Reynolds number.Nonlinear effects and LCO:Discussion regarding hysteresis and identification of the neutral stability pointDiscussion about experimental data sets, including a DLR study on LCO where there were trends with Mach numberProcess: Think about what questions we are trying to answerHow do we tell the organizing committee that we are participating by performing analyses? Is there a website sign up or abstract submittal form that we mail?

Note: following the end of the

telecon

, as the

webex

window was closing… it was noted that there were some questions and/or comments on the webex communication window. Apologies for not noticing them. The window closed before we could stop it. We are not smart enough to figure out the now-erased questions. Can you ask them again?Next telecon March 5, 11 a.m.

Slide43

Mini-abstract from AePW-1

MRL and USF Contribution to AePW - 1

N. N.

Thusiast

Multielement Research Lab, Mail Stop 000, Happy Forks, VA 00000 email: m.n.thusiast@mrl.gov, (777) 777-7777Soar N. Air†University of Southern Flight, Mail Code 98765, Lofty Heights, TX 00000 email: s.n.air@usf.edu, (888) 888-8888

We intend to participate in the AePW-1, to be held April 21-22 2012 in Honolulu, HI. We plan to perform the following sets of computations:

Configuration 1 – RSW , Steady Case,

. M=.825,

=2 degCode: RANS-CFD-3DGrid: Str-OnetoOne-C-v1 (supplied by AePW-1 committee)Turbulence model: Menter SSTConfiguration 1 – RSW , Unsteady Case, i. M=.825, =2 deg, 10 Hz Same as above

Configuration 2 – BSCW, Steady case, M=.85,



deg

, 10 Hz Same as above

Configuration 2 – BSCW,

Unteady

case, M=.85, =5 deg, 20 Hz Same as aboveConfiguration 3 - HIRENASD Configuration, steady, M=.8, Re=7 million, =1.5 degCode: RANS-CFD-3DAeGrid: Str-OnetoOne-C-v1 (supplied by AePW-1 committee)Turbulence model: S-AWe plan to submit our results electronically by the March 20, 2012 deadline to the AePW-1 committee. RANS-CFD-3DAe is a Reynolds-averaged Navier-Stokes code developed by Et et al.,1 widely used at theMultielement Research Lab. It is specifically formulated to work on three-element wing configurations. Ituses point-matched grids, and is an upwind finite-volume structured code.LES-CFD-3D is a large-eddy simulation code developed at the University of Southern Flight.2 It employs 6th order central differencing in space and 3rd order temporal differencing, along with 9th order explicit filtering.ReferencesEt, H., Cet, P., and Era L., “Description of RANS-CFD-3D,” Journal of Codes, Vol. 6, No. 5, 1994, pp. 5– 21.Author, A. and Author B., “Description of LES-CFD-3D,” Journal of Lengthy Papers, Vol. 9, No. 2, 2008, pp. 22–1021._ Corresponding Author. Senior Research Scientist, High Lift Branch.† Professor and Chair, Dept. of Aeronautical Engineering.1 of

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