===============
Turbine cascade
===============

:download:`Download this example <../../examples/turbine_cascade.yaml>`

Input file
==========


.. code-block:: yaml

   # Turbine cascade
   #
   # Run a stationary turbine cascade with prescribed flow angles.
   #


   # Use a new workdir for each run
   workdir: runs/*

   # Perfect gas inlet condition
   inlet:
     Po: 1e5
     To: 300.
     cp: 1005.
     gamma: 1.4

   # Set viscosity from Reynolds number
   Re_surf: 4e5

   # Turbine cascade design variables
   mean_line:
     type: turbine_cascade
     span: [0.01, 0.011]
     Alpha: [40., -65.0]
     Ma2: 0.6
     Yh: 0.029
     htr: 0.99

   # Setup annulus using fixed aspect ratios
   annulus:
     AR_gap: [1.0, 1.0]
     AR_chord: 2.0

   # Specify camber and thickness one one mid-span section
   blades:
       - spf: 0.5
         q_thick: [0.05, 0.12, 0.3, 0., 0.00, 0.18]
         q_camber: [10., -2., 0.0]

   # Discretise fluid domain using a coarse H-mesh
   mesh:
     type: h
     yplus: 30.0
     resolution_factor: 0.5

   # Use circulation for number of blades
   nblade:
     - Co: 0.7

   # Configure the built-in flow solver
   solver:
     type: emb
     n_step: 5000
     n_step_avg: 1000

Log output
==========

.. code-block:: none

    *** TURBIGEN v2.1.0 ***
    Starting at 2025-04-23T11:58:37
    Working directory: /builds/jb753/turbigen/runs/0001
    Inlet: PerfectState(P=1.000 bar, T=300.0 K)
    MeanLine(
        Po=[1.     0.9927] bar,
        To=[300. 300.] K,
        Ma=[0.311 0.6  ],
        Vx=[81.9 85.1] m/s,
        Vr=[0. 0.] m/s,
        Vt=[  68.7 -182.4] m/s,
        Vt_rel=[  68.7 -182.4] m/s,
        Al=[ 40. -65.] deg,
        Al_rel=[ 40. -65.] deg,
        rpm=[0. 0.],
        mdot=[5.66 5.66] kg/s
        )
    Designing annulus...
    FixedAR(nrow=1, x=[0.002625], r=[0.995], AR=[2.])
    Designing blades...
    Nblade: [473]
    Tip gaps: [0.]
    Re_surf=[4e+05]
    Generating mesh...
    Making an H-mesh...
    ncell/1e6=0.1
    Applying 2D guess...
    Initialising native solver...
    Patitioning onto 1 processors...
    Starting the main time-stepping loop...
    500: tpnps=3.168e-07, remaining=2m33s
      block 0: 6.94e-05 2.47e-02 4.72e-04 2.80e-02 6.06e+00
    1000: tpnps=3.168e-07, remaining=2m16s
      block 0: 2.19e-05 1.02e-02 2.19e-04 6.77e-03 2.57e+00
    1500: tpnps=3.150e-07, remaining=1m58s
      block 0: 7.31e-06 2.52e-03 7.27e-05 2.88e-03 6.81e-01
    2000: tpnps=3.157e-07, remaining=1m41s
      block 0: 1.97e-06 1.06e-03 1.62e-05 9.26e-04 1.70e-01
    2500: tpnps=3.150e-07, remaining=1m24s
      block 0: 5.64e-07 3.93e-04 6.78e-06 5.67e-04 6.09e-02
    3000: tpnps=3.152e-07, remaining=1m7s
      block 0: 1.47e-07 1.61e-04 1.28e-06 5.76e-05 1.75e-02
    3500: tpnps=3.250e-07, remaining=0m51s
      block 0: 8.86e-08 3.45e-05 5.53e-07 1.02e-04 5.85e-03
    4000: tpnps=3.176e-07, remaining=0m34s
      block 0: 1.24e-07 6.74e-05 6.25e-07 1.96e-04 3.70e-03
    4500: tpnps=3.207e-07, remaining=0m17s
      block 0: 1.37e-07 8.24e-05 1.04e-06 2.08e-04 8.38e-03
    4999: tpnps=3.192e-07, remaining=0m0s
      block 0: 1.40e-07 8.72e-05 1.13e-06 2.08e-04 9.90e-03
    Elapsed time 170.96s
    Average tpnps=3.177e-07
    mdot_in/out=5.63/5.63, err=-0.0%
    Variable  Nominal  Actual  Err_abs  Err_rel/%
    ---------------------------------------------
    Alpha[0]       40    39.8     0.24       0.59
    Alpha[1]      -65   -64.8    -0.25       0.38
         Ma2      0.6    0.59  0.00976       1.63
          Yh    0.029  0.0471  -0.0181      -62.3
         htr     0.99    0.99        0          0
     span[0]     0.01    0.01        0          0
     span[1]    0.011   0.011        0          0
          Ys           0.0471                    
          RR                1                    
     Beta[0]           0.0708                    
     Beta[1]           0.0313                    
    Efficiency/%: eta_tt=2.8, eta_ts=0.1

Plots
=====

.. image:: turbine_cascade.yaml_post_1.svg
   :width: 100%

.. image:: turbine_cascade.yaml_post_2.svg
   :width: 100%

.. image:: turbine_cascade.yaml_post_3.svg
   :width: 100%

.. image:: turbine_cascade.yaml_post_4.svg
   :width: 100%