Multiple bugs in Foil design (Windows 10) – one critical

I have significant experience with xflr5 and was excited to try flow5.  However, I’ve encountered a large number of bugs, one of which results in the results of airfoil analyses being useless.  I’ve listed the bugs in the order in which they are encountered when attempting to analyze airfoils.

1. Attempting to load a single airfoil from a dat file after airfoils are already in memory causes the creation of a new project containing only the airfoil being loaded.
   1. If the flow5 project has not been saved, a dialogue box will appear asking if the user wants to save the project.  Clicking “Yes” results in the “Save” window appearing, after which the existing project is closed and a new project is created that contains only the airfoil that was selected to be loaded.  Clicking “No” results in the existing project being closed without saving, and a new project is created that contains only the airfoil that was selected to be loaded.
   2. If the flow5 project has been saved, no dialogue box appears, the existing project is automatically closed, and a new project is created containing only the airfoil that was selected to be loaded.
   3. Attempting to load two or more airfoils from dat files does NOT cause the creation of a new project.  The airfoils are added to the existing project.
2. “Multi-threaded Batch Analysis” is greyed out and cannot be selected.  I tested this with imported airfoils from Selig format dat files (61 points each), and with internally generated N.A.C.A. airfoils (101 points each).  I tried it with a single airfoil in memory and with multiple airfoils in memory.  It was greyed out every time.
   
3. When defining an analysis, every boundary layer option is greyed out except for “Differential (experimental)”.
4. When defining an analysis, every analysis type option is greyed out except for “Type 1 (fixed speed)”.
5. The “alpha” symbol in the Analysis 2d sidebar appears as a box (unknown character).
   
6. When performing a flow analysis, the “Flow Analysis” log window is blank white (and subsequently becomes “Not Responding”) until the analysis finishes, at which point the window updates with the expected UI and log output.
   
7. CRITICAL – The results of an alpha sweep using options “Viscous”, “Init BL”, and “Store Opp” are wildly wrong.  The analysis was defined to be a “Type 1 (fixed speed)” analysis using the “Differential (experimental)” boundary layer because those were the only available options.
   1. I analyzed a S2091-101-83 airfoil with 61 points.  Re=1e6.  Alpha sweep from 0 to 20 degrees.
      1. The lift curve slope was 7.51 per radian.  Stall did not occur and the lift curve was linear.  Drag values were erratic and spiked to Cd>1.4  at Cl=2.1 before decreasing to near-zero at higher Cl.
         
   2. I repeated the analysis in xflr5 and obtained reasonable results.
      1. The lift curve slope was less 5.96 per radian (less than 2pi per radian, as expected).  The airfoil was predicted to stall at Cl=1.64.  The drag bucket was smooth and appeared as expected, including a slight laminar flow bucket.
         

Given that the airfoil analysis results are unreliable, I have not yet tried the “Plane design” module.