H OW TO CARRY OUT FUNDAMENTAL RESEARCH TOGETHER WITH INDUSTRY Lars Davidson Division of Fluid Dynamics Dept. of Mechanics and Maritime Sciences (M2) Chalmers
A PPLIED AND F UNDAMENTAL R ESEARCH I will show five nice examples of fundamental research carried out together with industry ◮ Water droplets/ruvulets on side mirrors ◮ Heat transfer in engines: exp & simulation ◮ External windnoise disturbing driver and passengers (automotive) ◮ Using active flow control for reducing drag on vehicles ◮ Heat transfer in engines: development of simulation method L. Davidson, FFI, April 2019 Applied and Fundamental 2 / 25
W ATER : V OLVO C ARS , FFI PROJECT , 2006-2011 U ∞ Water inlet L. Davidson, FFI, April 2019 Applied and Fundamental 3 / 25
W ATER : EXPERIMENT ( A ) Scatter plot. Air velocity V air = 13 ( B ) Different air velocities. F IGURE : Velocity of waterdrops that left the table. ρ ℓ h c V air = − 155 + 280 V air σ T. Tivert and L. Davidson Experimental study of water transport on a generic mirror, International Conference on Multiphase Flow,ICMF, Tampa, FL, US, 2010. L. Davidson, FFI, April 2019 Applied and Fundamental 4 / 25
E NGINES : V OLVO C ARS , FFI PROJECT , 2009-2014 Simplified case Piston top simplified as a series of horizontal and Real engine inclined plans Impinging jet flow and heat transfer L. Davidson, FFI, April 2019 Applied and Fundamental 5 / 25
E NGINES : EXP & SIMULATIONS ( A ) Setup ( B ) Computational domain F IGURE : Simplified setup M. Bovo and L. Davidson “Direct comparison of LES and experiment of a single-pulse impinging jet”, International Journal of Heat and Mass Transfer, Vol. 88, pp. 102-110, 2015. L. Davidson, FFI, April 2019 Applied and Fundamental 6 / 25
E NGINES : RESULTS Surface temperature Velocities at three instants wall normal velocity, 0 . 6 ms ( A ) Velocities at three instants. L. Davidson, FFI, April 2019 Applied and Fundamental 7 / 25
A COUSTICS , V OLVO & VCC, FFI PROJECT 2014-2018 W inds reen A-pillar Plenum Du k tail Hood z y x Beltline Side windo w Side mirror side mirror Cavity L. Davidson, FFI, April 2019 Applied and Fundamental 8 / 25
A ERO -V IBRO A COUSTICS : FFI PROJECT 2014-2018 An important source of the interior noise in vehicles is the window vibration that is excited by ◮ the exterior flow (indirect noise generation). ◮ the exterior flow-induced noise (direct noise transfer). Exterior side Vortices Noise from Noise from boundary layer vortices Boundary layer Structure Vibration Noise due to Noise due to hydrodynamic acoustic Interior side pressure pressure L. Davidson, FFI, April 2019 Applied and Fundamental 9 / 25
A PPLICATION 1 – G ENERIC S IDE -V IEW M IRROR (1) The exterior turbulence creates interior noise by making the window glass vibrate Generic side view mirror 0.1 0.1 0.1 Vortices Glass window 1.4 1.2 Pressure on window Glass window 0.1 GSV Mirror 0.8 Rigid plate 0.2 0.2 1.2 Cavity Y X Cavity 1.4 1.6 Pressure of interior noise Z ( A ) Domain with mirror, glass window ( B ) CFD, vibrating window, noise and cavity. propagation in cavity. H.-D. Yao & L. Davidson, “Generation of interior cavity noise due to window vibration excited by turbulent flows past a generic side-view mirror”, Phys. Fluids, Vol. 30, 036104, 2018 L. Davidson, FFI, April 2019 Applied and Fundamental 10 / 25
A PPLICATION 1 – G ENERIC S IDE -V IEW M IRROR (2) Compressibility: compressible vs. incompressible. Turbulence modeling: detached eddy simulation vs. large eddy simulation. Acoustics: direct vs. indirect simulation using acoustic perturbation equations. Grid topologies: trimmed vs. polyhedral cells. X (a) (a) Z X Z 4 3 2 1 (b) (b) Y X 6 7 5 Polyhedral mesh Trimmed mesh L. Davidson, FFI, April 2019 Applied and Fundamental 11 / 25
A PPLICATION 1 – G ENERIC S IDE -V IEW M IRROR (3) The contributions of the exterior hydrodynamic and acoustic pressure fluctuations to the interior noise generation are addressed. (a) C-DES C-LES -0.6 -0.3 z 0 0.3 0.6 I-DES with trimmed mesh I-DES with polyhedral mesh (b) -0.6 -0.3 z 0 0.3 0.6 0.3 0.6 0.9 1.2 0.3 0.6 0.9 1.2 x x 0.05 0.12 0.19 0.26 0.33 0.4 ( B ) SPLs of interior noise at Mic. 4 ( A ) RMS values of surface pressure (bottom corner) fluctuations L. Davidson, FFI, April 2019 Applied and Fundamental 12 / 25
A PPLICATION 2 – F ULL -S CALE T RUCK (1) The installation effect of a side-view mirror is studied. The simplification strategy for a full-scale production truck is validated. (a) Mirror bracket Upper mirror head Upper mirror head A-pillar Window Window (b) Bottom mirror head Mirror bracket Bottom mirror head Z Z X X Y Y Side-view mirror components, the A-pillar and the window Original and simplified trucks H.-D. Yao & L. Davidson, “Simplifications Applied for Simulation of Turbulence Induced by a Side View Mirror of a Full-Scale Truck Using DES”, SAE 2018-01-0708, 2018. H.-D. Yao, L. Davidson, Z. Chroneer, “Investigation of interior noise from generic side-view mirror using incompressible and compressible solvers of DES and LES”, SAE 2018-01-0735, 2018. L. Davidson, FFI, April 2019 Applied and Fundamental 13 / 25
A PPLICATION 2 – F ULL -S CALE T RUCK (2) A hybrid mesh of trimmed and polyhedral cells is employed. The mesh is sufficiently refined near the mirror and A-pillar to resolve turbulent flow structures. (a) Z X Y (Pa) Z (b) 100 X -120 -340 -560 ✲� ✁ ✂ Z X Y X Y ✲✄ ✂ ✂ ✂ Snapshots of Q-criterion A hybrid mesh of trimmed & polyhedral cells L. Davidson, FFI, April 2019 Applied and Fundamental 14 / 25
A ERODYNAMICS : AB V OLVO , FFI PROJECT 2013-2018 A−pillar L. Davidson, FFI, April 2019 Applied and Fundamental 15 / 25
U inf L. Davidson, FFI, April 2019 Applied and Fundamental 16 / 25
U inf L. Davidson, FFI, April 2019 Applied and Fundamental 16 / 25
U Jet inf Membrane Jet U inf 0 Time L. Davidson, FFI, April 2019 Applied and Fundamental 16 / 25
Jet Membrane Jet U inf 0 Time K D S z L y A W W L. Davidson, FFI, April 2019 Applied and Fundamental 16 / 25
Camera y/W 1 z L Side domain 0.5 B Rear R domain x U inf 1 1.6 x/W A U inf A B C y D AFC Laser L. Davidson, FFI, April 2019 Applied and Fundamental 17 / 25
G. Minelli, E. Adi Hartono, V. Chernoray, L. Hjelm and S. Krajnovic “Aerodynamic flow control for a generic truck cabin using synthetic jets”, Journal of Wind Engineering and Industrial Aerodynamics, Vol. 168, pp. 81-90, 2017. L. Davidson, FFI, April 2019 Applied and Fundamental 18 / 25
AFC OFF AFC ON G. Minelli, S. Krajnovic, B. Basara and B. Noack, “Numerical Investigation of Active Flow Control Around a Generic Truck A-Pillar”, Flow, Turbulence and Combustion, Vol. 97, pp. 1-20, 2016. L. Davidson, FFI, April 2019 Applied and Fundamental 18 / 25
E NGINES : AB V OLVO , FFI PROJECT ON - GOING valves spray piston F IGURE : Internal engine combustion of mixture of air and direct injected diesel. L. Davidson, FFI, April 2019 Applied and Fundamental 19 / 25
I MPINGING JET F IGURE : Turbulent axisymmetric impinging jet. L. Davidson, FFI, April 2019 Applied and Fundamental 20 / 25
T EST CASE U SED MESH TYPES Mesh for low-Reynolds- Mesh for high-Reynolds- Mesh for Numeric number, LRN, modeling number, HRN, modeling Wall Function, NWF L. Davidson, FFI, April 2019 Applied and Fundamental 21 / 25
W ALL FRICTION F IGURE : Impinging jet at Re D = 220000, comparing; : default LRN, : LRN with NWF mesh, face flux, : wall flux. L. Davidson, FFI, April 2019 Applied and Fundamental 22 / 25
S PEED - UP 3 , 470 LRN 313 HRN LRN w NWF mesh 624 Face flux 652 Wall flux 493 0 1 , 000 2 , 000 3 , 000 Steady-state solver time [s] J.-A. B¨ ackar, L. Davidson, “Evaluation of numerical wall functions on the axisymmetric impinging jet using OpenFOAM”, International Journal of Heat and Fluid Flow , Volume 67, pp. 27-42, Part A, 2017. L. Davidson, FFI, April 2019 Applied and Fundamental 23 / 25
✪ ✪ ✩ ✩ AFC AND M ACHINE LEARNING Project leaders: S. Krajnovi´ c and V. Chernoray ✑ ✒ ✎ ☎ ✆ ✝ ✞ � ✁ ✂ ✄ ✓ ✑ ✒ ✔✕ ✎ ✏ ☎ ✆ ✝ ✞ � ✁ ✂ ✄ ✟ ✠ ✡ ☛ ☞ ✌ ✍ ✓ ✔✕ ✏ ✟ ✠ ✡ ☛ ☞ ✌ ✍ �� Left: A sketch of the flow separation Right: The model placed in the wind tunnel Object: teach the controller to miminize drag by finding optimal A 1 , A 2 , f 1 , f 2 in S = A 1 sin( 2 π f 1 t ) + A 2 sin( 2 π f 2 t ) Learning procedure is based on a genetic algorithm (GA) optimization script L. Davidson, FFI, April 2019 Applied and Fundamental 24 / 25 ★ ❇ ❈ ❉ ❀ ❁ ❂❃ ✼ ✽ ✾✿ ✸ ✹ ✺✻ ✬ ✭ ✮✯ ✰ ✱ ✲ ✳ ❄ ❅ ❆ ■ ❏ ❑▲ ❊ ❋ ●❍ ✴ ✵ ✶✷ ✥ ✦ ✧ ✢ ✣ ✤ ✖ ✗ ✘ ✙ ✚ ✛ ✜ ✫ ★ ❇ ❈ ❉ ❀ ❁ ❂❃ ✼ ✽ ✾✿ ✸ ✹ ✺✻ ✬ ✭ ✮✯ ✰ ✱ ✲ ✳ ❄ ❅ ❆ ■ ❏ ❑▲ ❊ ❋ ●❍ ✴ ✵ ✶✷ ✥ ✦ ✧ ✢ ✣ ✤ ✖ ✗ ✘ ✙ ✚ ✛ ✜ ✫
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