PROJECT DETAIL · 2026

Optimal Pressure Sensor Placement for Reward Computation in RL-Based Active Flow Control

In-progress study on sparse pressure-probe layouts for reconstructing lift and quarter-chord pitching moment in DRL-driven airfoil flow control.

  • Current Focus
  • DRL
  • Active Flow Control
  • CFD
  • Research Tools

Problem Statement

Practical wind-tunnel-in-the-loop DRL requires reliable reward computation from limited pressure taps rather than full-field measurements.

Why It Matters

Quantifying where pressure-only sensing succeeds or fails is important for experimental AFC reward design and sensor budgeting.

Methods / Numerical + ML Setup

  • Studied a 3D NACA0024 airfoil at 8° incidence and chord-based Reynolds number 60,000.
  • Generated time-resolved pressure fields for uncontrolled and actuated cases using wall-resolved implicit LES in PyFR.
  • Trained regression models to reconstruct lift and quarter-chord pitching moment from sparse pressure signals over DRL-relevant control intervals.
  • Formulated sensor placement as a constrained optimization problem with a fixed pressure-tap budget.

Key Results

  • Established reconstruction-error bounds across candidate sensor budgets.
  • Derived practical placement guidelines for pressure taps in future DRL wind-tunnel campaigns.

Toolchain

  • PyFR
  • Python
  • Regression modeling
  • Optimization workflows
  • Active flow control setup

Challenges and Lessons

  • Balancing reconstruction accuracy against strict sensor-count constraints.
  • Maintaining robust estimates under unsteady actuation and transitional flow behavior.

Future Work

  • Integrate optimized tap layouts into real-time reward computation during closed-loop DRL experiments.
  • Extend sensor-placement studies across broader operating envelopes and control objectives.

Prasanna Thoguluva Rajendran · Ph.D. Student in Aerospace Engineering · University of Arizona, Tucson, AZ