What the Airfoil Agent Does
The airfoil agent supports these skills:
generate-cfd-mesh: build CFD mesh and mesh-quality outputs.run-cfd-simulation: run steady CFD from an existing mesh.run-aero-optimization: run single-point aerodynamic optimization.
Standard Inputs
airfoil_profile(str, default: “naca0012”): airfoil name (for example “naca0012”, “rae2822”).mesh_cells(int, default: 6000): target total mesh-cell count for the airfoil mesh workflow.y_plus(float, default: 50.0): target near-wall spacing in wall units (y+) used to estimate the first-layer cell size d0 when it is not provided.mach_number(float, default: 0.2): freestream Mach number used together with y_plus and reynolds_number to estimate the near-wall first-layer cell size d0 when it is not provided.reynolds_number(float, default: 5e6): freestream Reynolds number used together with y_plus and mach_number to estimate the near-wall first-layer cell size d0 when it is not provided.local_refine_box(list[list[float]], default: None): optional two-corner local refinement box[[x0, y0, z0], [x1, y1, z1]]; leave unset for no local refinement.
angle_of_attack(float, default: 2.0): angle of attack in degrees.fixed_lift_coeff(float, default: -1.0): automatically vary the angle of attack to compute drag at the prescribed lift coefficient. Set it to -1.0 to disable.airfoil_profile(str, default: inherited from mesh step): airfoil profile name inherited from generate-cfd-mesh and used to fit CST coefficients when needed.mach_number(float, default: inherited from mesh step): freestream Mach number.reynolds_number(float, default: inherited from mesh step): freestream Reynolds number.y_plus(float, default: inherited from mesh step): target near-wall y+ inherited from generate-cfd-mesh and used to auto-select wall functions.cst_coeffs(list[float], default: None): optional CST vector [upper…, lower…]; if omitted, prepare fits the coefficients automatically.n_cpu_cores(int, default: 1): MPI ranks/CPU cores.
angle_of_attack(float, default: 2.0): initial angle of attack in degrees.airfoil_profile(str, default: inherited from mesh step): airfoil profile name inherited from generate-cfd-mesh and used to fit CST coefficients when needed.mach_number(float, default: inherited from mesh step): freestream Mach number.reynolds_number(float, default: inherited from mesh step): freestream Reynolds number.y_plus(float, default: inherited from mesh step): target near-wall y+ inherited from generate-cfd-mesh and used to auto-select wall functions.optimizer(str, default: “SLSQP”): optimizer (“SLSQP”, “IPOPT”, “SNOPT”).lift_constraint(float, default: 0.5): minimum lift coefficient target.max_opt_iters(int, default: 50): max optimization iterations.thickness_constraint(float, default: 0.5): minimum normalized thickness (negative disables).le_radius_constraint(float, default: 0.7): minimum normalized leading-edge radius (negative disables).volume_constraint(float, default: 1.0): minimum normalized airfoil volume (negative disables).cst_coeffs(list[float], default: None): optional initial CST vector [upper…, lower…].n_cpu_cores(int, default: 1): MPI ranks/CPU cores.
Advanced Parameters
blunt_te(float, default: 0.01): trailing-edge round percentage expressed as an x/chord trim location; 0.01 means the trim starts at x = 0.01 from the trailing edge.d0(float, default: -1.0): first-layer height in meters; use a negative value to estimate it from y_plus, mach_number, and reynolds_number.hyperbolic_sweeps(int, default: 20): number of smoothing sweeps per layer for hyperbolic extrusion.neighbor_rings(int, default: 5): neighbor-ring depth used by the hyperbolic extrusion smoother.diffuse_start(float, default: 0.002): smoothing onset distance in meters for hyperbolic diffusion.max_nonorthogonality_pass(float, default: 70.0): pass threshold for maximum non-orthogonality.max_nonorthogonality_warning(float, default: 80.0): warning threshold for maximum non-orthogonality.max_aspect_ratio_pass(float, default: 1000.0): pass threshold for maximum aspect ratio.max_aspect_ratio_warning(float, default: 5000.0): warning threshold for maximum aspect ratio.max_skewness_pass(float, default: 4.0): pass threshold for maximum skewness.max_skewness_warning(float, default: 6.0): warning threshold for maximum skewness.
transonic_mach_boundary(float, default: 0.4): Mach-number boundary used by the default Mach-based solver selection when solver_name is not provided.solver_name(str, default: null): explicit solver override; leave unset to use the default Mach-based solver selection.turbulence_model(str, default: “SpalartAllmaras”): OpenFOAM RANS turbulence model (“SpalartAllmaras”, “kOmegaSST”).use_wall_functions(str, default: “auto”): wall-function selection (“auto”, “1”, “0”).max_flow_iters(int, default: 10000): maximum flow iterations written to the case control settings.n_cst_coeffs(int, default: 6): number of CST coefficients per surface used when prepare fits CST coefficients.primal_func_std_tol(float, default: 0.04): DAFoam primal function standard deviation tolerance.primal_func_slope_tol(float, default: 1e-6): DAFoam primal function slope tolerance.force_std_pass(float, default: 0.0001): pass threshold for raw force-coefficient standard deviation.force_std_warning(float, default: 0.05): warning threshold for raw force-coefficient standard deviation.residual_drop_orders_pass(float, default: 6.0): pass threshold for minimum residual drop in log10 orders.residual_drop_orders_warning(float, default: 3.0): warning threshold for minimum residual drop in log10 orders.initialize_from(str, default: null): warm-start source case name; leave unset for a cold start.cp_plot_lower_bound(float, default: -2.0): lower bound of the Cp axis and colorbar.cp_plot_upper_bound(float, default: 2.0): upper bound of the Cp axis and colorbar.u_plot_lower_bound(float, default: -1.0): lower bound of the normalized velocity colorbar.u_plot_upper_bound(float, default: 1.0): upper bound of the normalized velocity colorbar.
transonic_mach_boundary(float, default: 0.4): Mach-number boundary used by the default Mach-based solver selection when solver_name is not provided.solver_name(str, default: null): explicit solver override; leave unset to use the default Mach-based solver selection.turbulence_model(str, default: “SpalartAllmaras”): OpenFOAM RANS turbulence model (“SpalartAllmaras”, “kOmegaSST”).use_wall_functions(str, default: “auto”): wall-function selection (“auto”, “1”, “0”).max_flow_iters(int, default: 10000): maximum flow iterations written to the case control settings.max_adj_iters(int, default: 1000): maximum GMRES iterations for the DAFoam adjoint linear solve.pc_fill_level(int, default: 1): ILU fill level for the DAFoam adjoint preconditioner.n_cst_coeffs(int, default: 6): number of CST coefficients per surface used when prepare fits CST coefficients.primal_func_std_tol(float, default: 0.04): DAFoam primal function standard deviation tolerance.primal_func_slope_tol(float, default: 1e-6): DAFoam primal function slope tolerance.objective_reduction_pct_pass(float, default: 5.0): pass threshold for objective reduction in percent.objective_reduction_pct_warning(float, default: 1.0): warning threshold for objective reduction in percent.final_feasibility_pass(float, default: 0.0001): pass threshold for final feasibility.final_feasibility_warning(float, default: 0.01): warning threshold for final feasibility.flow_residual_drop_orders_pass(float, default: 6.0): pass threshold for minimum flow residual drop in log10 orders.flow_residual_drop_orders_warning(float, default: 3.0): warning threshold for minimum flow residual drop in log10 orders.adjoint_residual_drop_orders_pass(float, default: 5.0): pass threshold for minimum adjoint residual drop in log10 orders.adjoint_residual_drop_orders_warning(float, default: 3.0): warning threshold for minimum adjoint residual drop in log10 orders.cp_plot_lower_bound(float, default: -2.0): lower bound of the Cp axis and colorbar.cp_plot_upper_bound(float, default: 2.0): upper bound of the Cp axis and colorbar.u_plot_lower_bound(float, default: -1.0): lower bound of the normalized velocity colorbar.u_plot_upper_bound(float, default: 1.0): upper bound of the normalized velocity colorbar.
Agent Capability demos
Mesh Generation
Users can prompt to generate airfoil mesh with desired airfoil profiles, mesh densities, yPlus, and local refinement.
Fig. 1. Top left: Overview of a coarse mesh. Prompt: Generate a cfd mesh for the naca0012 airfoil. Top right: Trame interactive view of the TE mesh. Bottom left: Overview of a fine mesh with a different airfoil. Prompt: Generate a cfd mesh for the rae2822 airfoil with 50K cells, yPlus 3, and ref Mach=0.7. Bottom right: Locally refined mesh. Prompt: Locally refine the above mesh between -0.1 to 1.1 chords from LE, z length of the refinment is 0.5 chords.
CFD Simulation
Users can prompt to run airfoil CFD simulations with desired airfoil profiles (prescribed in the mesh generation skill), angles of attack, Mach numbers, and Reynolds numbers. For example,
Generate a cfd mesh for the naca0012 airfoil and run a cfd simulation at Ma=0.3, Re=5e6, and aoa=3 degs. Use 2 CPU cores.
Or a supersonic flow case
Generate a cfd mesh for rae2822 airfoil with 100K cells, yPlus 5, Re 2e7 and Ma 1.5. Run a cfd with aoa=1 deg use 4 cores..
The following are the agent-generated figures.
Fig. 2. Top left: Airfoil pressure profile. Top right: Visualization of airfoil turbulence variable field in the trame interactive server. Bottom left and right: pressure and velocity contours of the supersonic csaae.
CFD Mesh Convergence Study
Users can prompt to conduct a mesh convergence study for an airfoil. For example,
Conduct a cfd mesh convergence study for the RAE2822 airfoil at Ma=0.75, Re=1e7, and aoa=2 degs. The mesh sizes are 10K, 20K, 50K, and 100K. The yPlus is 3. Use 24 cores. CFD maxIter=5000.
The following is the agent-generated figure, one needs to add a follow up prompt to plot this pressure profile comparisoin figure, such as
Plot the pressure profile for all cases in one figure to show the difference.
Fig. 3. Pressure profile comparison between different mesh densities.
CD/CL vs AoA
Users can prompt to simulation CD/CL sweep for various angle of attacks. For example,
Generate a cfd mesh for the naca0012 airfoil with 50K cells and yPlus 3. Then, run a sweep of CFD at Ma=0.3 and Re=5e6, and aoa = 2 to 18 degs with 2 deg interval. Use 24 cores. After the simulation is finished, plot cl/cd vs aoa and drop diverged cases..
The following is the agent-generated figure. This case ran on the HPC and you may need to follow up to ask the agent to analyze the result once the job is finished on compute nodes.
Fig. 4. CD/CL vs AoA plots
Aerodyanamic shape optimization
Users can prompt to run aerodynamic shape optimization. The default objective is drag, the design variabels are airfoil shape and angle of attack, the constraints include lift, thickness, volume, and leading edge radius. For example,
Generate a cfd mesh for the naca0012 airfoil and run an aero optimization at ma 0.3, re 5e6, cl 0.5. Run the optimization for 20 iters. Use 2 cores.
The following is the agent-generated figure. The drag reduction and constraints can be found in the chat window after the optimization is finished. After the optimization is finished, the user can also ask agent to verify the drag reduction generated by the coarse-mesh optimization with a fine mesh. For example
The optimization uses a coarse mesh. Verify the optimization drag reduction at CL 0.5 using a fine mesh with 50K cells and yPlus 3. Run two fine mesh CFDs for the baseline and optimized designs and compare with the coarse mesh results.
The agent will compare the drag reduciton between coarse and fine mesh for the baseline and optimized designs.
Fig. 5. Aerodynamic optimization. Top Left: comparison of the pressure and shape between the baseline and optimized designs. Top Right: Visualizing of the pressure for optimized design in trame. Bot left: Optimization convergence history for CD. Bot right: Summary of fine mesh verification.