1 Distribution A. Approved for public release; distribution is unlimited. Integrity  Service  Excellence Aerospace Vehicles Division April 2015 Brock Pleiman Aerospace Vehicles Division Aerospace Systems Directorate Air Force Research Laboratory Presented to the AFRL/NASA SBLI Technical Interchange Meeting, Ohio Aerospace Institute, Dayton, Ohio Comparison of Experimental data and CFD simulations in a Sub-Scale Mixed Compression Inlet

2 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

3 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

4 Distribution A. Approved for public release; distribution is unlimited. SWBLI Motivation Regain 4 th gen. inlet aerodynamic performance while moving beyond 5 th gen. survivability

5 Distribution A. Approved for public release; distribution is unlimited. CFD Motivation AFRL/RQVI would collaborate with LM to conduct CFD and assess how well the simulations could compare to previously run experimental set-ups. –Static pressure taps along the surface of the model and total pressure rakes at the entrance and exit of the diffuser were used to determine if/when CFD solution diverged from experimental results. –CFD results could be used to determine how the flow behaved in areas where CFD and Exp. results agreed.

6 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

7 Distribution A. Approved for public release; distribution is unlimited. CFD Set-up # of cells: –15.2 mill Cells in spanwise and vertical dimension: –135x105 Max cell size in throat region: –~0.03” Model Length: –2.3’ or 27.6” Reverse Bleed: –RANS: Enabled –DES: Disabled Reynolds #: –3.169x10 6 /foot Mach at entrance: –~3 Best case downstream bleed configuration from experimental results

Detailed Comparison With Experimental Data Sonic line Cowl Bleed Throat Bleed Ramp Bleed #1Ramp Bleed #2Throat Bleed Cowl Center Line Ramp Center Line Sep 1 Shk Bleed 1 Realign Shk Sep1 Exp Sep 1 Realign Shk Sep 2 Shk Sep 2 Exp Term Shk Bleed 3 Realign Shk Bleed 5 Sep Shk 1 Bleed 3 Corner Exp Sep 2 Shk Sep 2 Exp Sep 1 Realign Shk & Bleed 1 Realign Shk Bleed 3 Exp Bleed 3 Realign Shk Bleed 1 Bleed 2 Sep Shk 2 Bleed 2 Exp Bleed 2 Realign Shk Corner Exp Term Shk Bleed 4 Bleed 5 Realign Shk & Term Shk Bleed 5 Exp Sep 1 Sep 2 Sep 3 Sep 3 Realign Shk Upper: RANS

9 Distribution A. Approved for public release; distribution is unlimited. RANS Detailed Analysis 70.1% recovery Run 12 Point 12 Experimental 40 probe Interpolation* FLA Run 12 Point 12 Full RANS Result FLA 76.4% recovery Final Conclusion: Although the RANS solution accurately predicts the centerline wall surface pressures up to the diffuser entrance, the simulation breaks down for unknown reasons and thus results in a pattern that is rotated 90º

10 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

11 Distribution A. Approved for public release; distribution is unlimited. RANS Flow Development Video Note the creation and growth of the corner vortex

12 Distribution A. Approved for public release; distribution is unlimited. Image of Isolator location Rake Location

13 Distribution A. Approved for public release; distribution is unlimited. RANS Isolator Solution Note that the corner separation has already grown to size that dominates the flow

14 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

15 Distribution A. Approved for public release; distribution is unlimited. DES Solution *Video is courtesy of Lockheed Martin SWBLI Model only has steady state probes. A “steady state” needed to be computed for the DES Color code: Red – Bleed Green – Reverse bleed (Disabled) Light Gray - Separation

16 Distribution A. Approved for public release; distribution is unlimited. Time Averaging and “Steady State” Assumption The DES simulation was run for 3.65msec or 1 cycle Averaging over the complete time frame of the cycle would therefore create a “steady state” Shown below is a result of averaging of all 75 discrete time steps into one contour plot * Note Color map is not equivalent to those shown before

17 Distribution A. Approved for public release; distribution is unlimited. Image of DES average at Isolator location The averaged DES solution shows a nearly symmetrical pattern which was expected. Also note that a small pressure recovery hole is shown in the middle of the stream.

18 Distribution A. Approved for public release; distribution is unlimited. Ramp/Floor Isolator pressure taps CFD TypeMax Error (Approx.) Min Error (Approx.) Follows Exp. Trend DES0.0850Yes RANS0.0850No

19 Distribution A. Approved for public release; distribution is unlimited. Side Wall Isolator Pressure Taps CFD TypeMax Error (Approx.) Min Error (Approx.) Follows Exp. Trend DES Yes RANS0.4.32No

20 Distribution A. Approved for public release; distribution is unlimited. Corner Isolator Pressure Taps CFD TypeMax Error (Approx.) Min Error (Approx.) Follows Exp. Trend DES0.250No RANS No

21 Distribution A. Approved for public release; distribution is unlimited. Detailed Comparison With Experimental Data Sonic line Cowl Bleed Throat Bleed Ramp Bleed #1Ramp Bleed #2Throat Bleed Cowl Center Line Ramp Center Line Sep 1 Shk Bleed 1 Realign Shk Sep1 Exp Sep 1 Realign Shk Sep 2 Shk Sep 2 Exp Term Shk Bleed 3 Realign Shk Bleed 5 Sep Shk 1 Bleed 3 Corner Exp Sep 2 Shk Sep 2 Exp Sep 1 Realign Shk & Bleed 1 Realign Shk Bleed 3 Exp Bleed 3 Realign Shk Bleed 1 Bleed 2 Sep Shk 2 Bleed 2 Exp Bleed 2 Realign Shk Corner Exp Term Shk Bleed 4 Bleed 5 Realign Shk & Term Shk Bleed 5 Exp Sep 1 Sep 2 Sep 3 Sep 3 Realign Shk RANS

22 Distribution A. Approved for public release; distribution is unlimited. Detailed Comparison With Experimental Data Subsonic Diffuser RANS

23 Distribution A. Approved for public release; distribution is unlimited. Exp. Vs. DES 40 point interpolation solution Exp. 40 probe Interpolated Solution DES 40 Probe Interpolated Solution 76.4% recovery – 40 probe 77.6 % recovery – Interpolated 66.9% recovery – 40 probe 68.2% recovery – Full CFD Solution Although both results show a similar AIP pressure recovery pattern the total pressure recovery for the DES simulation is less than the experimental. This may be due to reversed bleed flows in the throat that could occur in the experiment but boundary conditions did not allow in the simulation.

24 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

25 Distribution A. Approved for public release; distribution is unlimited. Future Plans Lockheed Martin has installed Falcon on AFRL supercomputing network and will collaborate with AFRL/RQVI to run DES simulations: –Reverse Bleed enabled SWBLI at Run 12 Point 12 –Run RANS analysis from 0.3’ on the model to the AIP with the flow profile predicted by DES –Modified bleed configuration proposed by LM –More concentrated corner bleed configurations –Low bleed mixing devices Re-Vector to support FAD

26 Distribution A. Approved for public release; distribution is unlimited. Briefing Content SWBLI Motivation Previous Analysis Recap Additional RANS Analysis DES Analysis Future Plans Questions

27 DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution Distribution A. Approved for public release; distribution is unlimited.