Additional On-Surface and Off-Surface Aerodynamic Data for Partially-Dressed Cavity-Closed Nose Landing Gear Benchmark (PDCC-NLG)

Additional On-Surface and Off-Surface

Aerodynamic Data for Partially-Dressed

Cavity-Closed Nose Landing Gear Benchmark

(PDCC-NLG)

Mehdi R. Khorrami and Dan H. Neuhart

NASA Langley Research Center

Workshop on Benchmark problems for Airframe Noise Computations

(BANC-1)

Stockholm, Sweden, June 10-11, 2010

PDCC - NLG

 11 Dynamic Pressure Transducers (1 Roving)  ~123 Static Pressure Ports  Mobile sensor placed at various hot spots during 2008 entry Unsteady pressures (fixed probes) + PIV data D. H. Neuhart et al. [AIAA 2009-3152] Lower arm Unsteady pressures (mobile sensor) + additional Upper door PIV data provide further insight into flow field Lower drag-link Upper drag-link

Fixed vs. Mobile Sensor

Lower arm Upper door Lower drag-link Upper drag-link

Lower Torque-Arm

Front side Back side Flow

Upper Torque-Arm

Back side Flow

Door Front Side

Door Backside

(Horizontal Rows)

b) a) a b c d d) c)

Door Backside

(Vertical Rows)

a) b) b c a c)

PIV Planes

4 3 1 7 6 5 2 Starboard Port

PDCC vs. FDCO Surface Pressures

Lower arm Upper door Wheel outer Lower drag-link Upper drag-link Lower arm Wheel inner

FDCO vs PDCC Comparison

PDCC FDCO Displayed plane FDCO PDCC PDCC FDCO

X-Z Plane PIV Measurements

6 5 4 3 1 7 2 1) 6) Starboard Port 2) 4) 3)

Summary

 Unsteady surface pressures from the mobile sensor confirm the

broadband nature of, and lack of any tonal character in, the

pressure field, corroborating previous results obtained with the

fixed sensors

 The shock-strut torque-arm combination produces flow

interactions reminiscent of tandem cylinder flow field

 The X-Z PIV planes downstream of the wheels show the wake to

be symmetric

 A collective decision must be made as to whether the present

data should be added to the PDCC-NLG dataset

 What more can be done and how else can we improve the dataset

for the PDCC-NLG benchmark?

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