Shape optimization of a feedback-channel fluidic oscillator

Figures & data

Figure 1. A schematic of the fluidic oscillator and computational domain.

Figure 2. Geometric parameters.

Figure 3. Optimization procedure.

Table 1. Design space.

Design variable	Lower limit	Reference	Upper limit
w/dth	0.19	0.37	0.94
ds/dth	0.53	1.45	2.34

Figure 4. Grid dependency test for frequency of flow oscillations at the feedback channel of the reference fluidic oscillator (Jeong & Kim, 2016).

Figure 5. Validation of numerical results with three turbulence models using experimental data for the frequency of flow oscillation (Jeong & Kim, 2016).

Table 2. Design variables and objective function values at all the LHS design points.

	Design variables		Objective functions
Design point	w/dth	ds/dth	FVR	Ff
1	0.934	1.921	−2.188	0.190
2	0.417	0.570	−2.348	0.365
3	0.774	1.459	−2.096	0.232
4	0.526	1.726	−1.443	0.209
5	0.272	0.974	−1.060	0.199
6	0.727	2.311	−1.828	0.164
7	0.279	1.997	−0.898	0.181
8	0.636	0.742	−2.331	0.277
9	0.459	1.215	−1.510	0.190
10	0.901	0.799	−2.943	0.391

Figure 6. Pareto-optimal fronts with RSA and KRG models.

Figure 7. Representative Pareto-optimal designs.

Table 3. Design variables and objective function values at four cluster points and the reference design.

	Design variables		Surrogate prediction		URANS calculation		Relative error [%]
Cluster	w/dth	ds/dth	FVR	Ff	FVR	Ff	FVR	Ff
RSA-A	0.932	0.628	−3.309	0.452	−3.362	0.435	1.58	3.85
RSA-B	0.931	0.904	−2.916	0.374	−2.986	0.362	2.33	3.49
RSA-C	0.933	1.192	−2.602	0.306	−2.653	0.299	1.92	2.39
RSA-D	0.933	1.608	−2.234	0.204	−2.315	0.198	3.4	3.34
KRG-A	0.932	0.663	−3.252	0.444	−3.349	0.420	2.89	5.83
KRG-B	0.932	0.901	−2.917	0.378	−3.029	0.360	3.68	5.03
KRG-C	0.932	1.233	−2.564	0.296	−2.612	0.281	1.84	5.24
KRG-D	0.932	1.679	−2.301	0.221	−2.255	0.209	2.05	5.32
Reference	0.370	1.450	–	–	−1.226	0.221	–	–

Figure 8. Frequency of flow oscillation at the feedback channels.

Figure 9. Time-resolved mass flow rate through a right-hand side feedback channel for the PODs.

Table 4. Time-averaged mass flow rate through the right-hand side feedback channel for the PODs.

	POD A	POD B	POD C	POD D
Time-averaged Mass flow rate [kg/s]	0.179	0.183	0.187	1.181

Figure 10. Local velocity ratio distributions and velocity vectors at t = T/4 and 3T/4 on the central x-y plane (z = 0) for POD A, POD D, and the reference design.

Figure 11. Vorticity (ω_z) distributions at t = T/4 on the central x-y plane (z = 0) for POD A, POD D, and the reference design.

Figure 12. Local velocity ratio distributions and streamlines at t = T/4 on the cross-sectional plane A-A’.

Figure 13. Local velocity ratio distributions at t = T/4 and 3T/4 on outlet plane for POD A, POD D, and the reference design.

Jeong, H.-S., & Kim, K.-Y. (2016). Effects of fluidic oscillator geometry on performance. Journal of Computational Fluids Engineering, 21(3), 77–88. doi: 10.6112/kscfe.2016.21.3.077

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