High-Order Accurate Numerical Simulations of Flow around a - - PowerPoint PPT Presentation
Introduction Base Phantom Yaw LSB Conclusion High-Order Accurate Numerical Simulations of Flow around a Projectile using PyFR Jin Seok Park 1 1 Agency For Defense Development, South Korea PyFR Symposium 2020 1/39 Introduction Base Phantom
Introduction Base Phantom Yaw LSB Conclusion
Jin Seok Park1
1Agency For Defense Development, South Korea
PyFR Symposium 2020
1/39
Introduction Base Phantom Yaw LSB Conclusion
1
Introduction
2
Subsonic Flow around Projectile Base
3
Flow around Cylindrical Body at High Angle of Attack
4
Laminar Separation Bubble on Low-Reynolds Number Aerofoil
5
Conclusion
2/39
Introduction Base Phantom Yaw LSB Conclusion
The Center for the Development of Defense Science and Technology at South Korea
3/39
Introduction Base Phantom Yaw LSB Conclusion
Analyse aerodynamics around missile via various methods
Semi-empirical methods Computational Fluid Dynamics Wind-tunnel test Flight test
Wind-tunnel Facilities
4/39
Introduction Base Phantom Yaw LSB Conclusion
GPU Supercomputer @ ADD 1280 Intel Xeon Gold CPU (@3.5Ghz) - 140 DP-TFLOPS/s
40 NVIDIA Tesla P100 GPU (@3.2Ghz) - 212 DP-TFLOPS/s
5/39
Introduction Base Phantom Yaw LSB Conclusion
Weak scaling on ADD Supercomputer
5 10 15 20 25 30 35 0.5 1 1.5 2
1 Billion DOFs at 94.3TFLOP/s, 55.7% Peak FLOP/s on 0.1M CUDA cores
Number of GPU Normalised Run-time
6/39
Introduction Base Phantom Yaw LSB Conclusion
Strong scaling on ADD Supercomputer
5 10 15 20 25 30 2 4 6 8
6.26x faster, 84.9TFLOP/s, 50.1% Peak FLOP/s, 12% Loading/GPU
Number of GPU Speed-up
7/39
Introduction Base Phantom Yaw LSB Conclusion
Linearized and slender-body aerodynamics at low angle of attack (except transonic flow) Highly non-linear flow regime
Asymmetric body vortex and interactions Strong shock interactions
Classification of Missile Aerodynamics (F. G. Moore) Body and fin-shed vortex modeling(J. B. Doyle et al., AIAA 2015-2587) 8/39
Introduction Base Phantom Yaw LSB Conclusion
Conventional CFD methods predicts steady-state aerodynamics well.
2nd-order accurate spatial discretization RANS turbulent models
Highly non-linear flow regime
High-Order accurate methods can potentially resolve detailed flow structure
9/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
1
Introduction
2
Subsonic Flow around Projectile Base Overview Methodology Results
3
Flow around Cylindrical Body at High Angle of Attack
4
Laminar Separation Bubble on Low-Reynolds Number Aerofoil
5
Conclusion
10/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Highly-Separated flow at the base1
11/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
RANS simulation cannot resolve detailed flow strucute around the end of base. Inaccurate prediction of base drag
12/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Reliable Experimental Data
Base pressure and base velocity are measured2
ReD = u∞d/ν = 9.6 × 104, M = 0.1 Wall-resolved ILES 3:1 Elliptic nose and cylinder body
l = 400mm,d = 70mm
Base Pressure and Near-Wake Flow Features of an Axisymmetric Blunt-Based Body. Exp Fluids. 2013
13/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Previous numerical study3
VMS-LES @ ReD = 9.6 × 104 DNS @ ReD = 1500
Relation between base pressure and the size of recirculation
Characteristics and Wake Mean Recirculation Length of an Axisymmetric Blunt-Based Body, J. Fluids and
14/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
5th-order accurate FR scheme, Wall-resolved ILES
Long-period averaging over 150Tc(= d/u∞)
Quadratically curved tetrahedral meshes
0.32M tet elements
15/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
16/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged Pressure coefficients at base Cpr/d<0.4 = 0.1606
17/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged pressure contour with streamline at wake region Recirculation region lr/d = 1.20
18/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
1
Introduction
2
Subsonic Flow around Projectile Base
3
Flow around Cylindrical Body at High Angle of Attack Overview Methodology Results
4
Laminar Separation Bubble on Low-Reynolds Number Aerofoil
5
Conclusion
19/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Asymmetric shedding of body vortices at high angle of attack4 Strongest in the subsonic regime
Phantom Yaw
20/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Experimental and numerical studies to measure force5 ReD = 200, 000 Ogive-Cylinder body with fineness ratio 2.5 and 3.5 nose.
5E.S. Lee et al., Experimental Reproduction and Numerical Analysis of the Side Force on an Ogive Forebody
at High Angle of Attack, KSCFE, 2013
21/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Peak of the side force occurs at 50 degree angle of attack Convective instability at 46 degree angle of attack Global instability at higher angle of attack
Three stable states.
22/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
ReD = u∞d/ν = 200, 000, M = 0.1 50 degree angle of attack, Every 60 degree of roll angle 4th-order accurate FR scheme, Wall-resolved ILES
Long-period averaging over 50Tc(= d/u∞)
Ogive-Cylinder with fineness ratio 3.5 nose and fineness ratio 4.0 body Quadratically curved tetrahedral meshes
0.59M tet elements
23/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
ReD = u∞d/ν = 200, 000, M = 0.1 50 degree angle of attack, Every 60 degree of roll angle 4th-order accurate FR scheme, Wall-resolved ILES
Long-period averaging over 50Tc(= d/u∞)
Ogive-Cylinder with fineness ratio 3.5 nose and fineness ratio 4.0 body Quadratically curved tetrahedral meshes
0.59M tet elements
23/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
24/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Constant normal force along the bank angle Changes in side force
Three stable states : Cy = 0, 0.25, 0.5
25/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Large side force occurs at ogive nose. Three stable states of sectional distribution
φ = 0, 60, 120◦ φ = 240◦ φ = 180, 300◦
26/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged Q-Crierion
φ = 0, 60, 120◦: Slightly inclined vortex structures after mid nose φ = 240◦: Close and Inclined vortex structures φ = 180, 300◦: Almost symmetric vortex Figure: φ = 0◦ Figure: φ = 60◦ Figure: φ = 240◦ Figure: φ = 300◦
27/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
1
Introduction
2
Subsonic Flow around Projectile Base
3
Flow around Cylindrical Body at High Angle of Attack
4
Laminar Separation Bubble on Low-Reynolds Number Aerofoil Overview Methodology Results
5
Conclusion
28/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Benchmark test case at Korean Society for Aeronautical and Space Sciences (KSAS)6
KSAS EFD (Experimental Fluid Dynamics)-CFD Session Experimental data (KARI)
Re=27,500 M = 0.48, various angle of attacks
PyFR, KSAS 2018
29/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Non-linear aerodynamics due to Laminar separation bubble Abrupt change of transition point around 4 ∼ 5◦ AoA
30/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
4th-order accurate FR scheme, Wall-resolved ILES Quadratically curved hexahedral meshes
0.13M hexahedral elements
31/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Angle of attacks = 3◦
32/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Angle of attacks = 7◦
33/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged velocity contour Separation and reattachment around trailing edge
34/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged velocity contour Separation bubble movies forward.
35/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged velocity contour Stall occurs at angle of attack 9◦
36/39
Introduction Base Phantom Yaw LSB Conclusion Overview Methodology Results
Time-averaged lift coefficient
37/39
Introduction Base Phantom Yaw LSB Conclusion
PyFR can resolve highly non-linear flow structure around a projectile
Subsonic base flow Body vortex at high angle of attack
Additional requirements of high-order method for missile aerodynamics
Resolve interactions of body and fin vortex Resolve strong shock and iterations Aeroheating of supersonic and hypersonic projectile
38/39
Introduction Base Phantom Yaw LSB Conclusion
PyFR can resolve highly non-linear flow structure around a projectile
Subsonic base flow Body vortex at high angle of attack
Additional requirements of high-order method for missile aerodynamics
Resolve interactions of body and fin vortex Resolve strong shock and iterations Aeroheating of supersonic and hypersonic projectile
38/39
Introduction Base Phantom Yaw LSB Conclusion
39/39