‎ Using the Risk Manager for Helideck Turbulence Studies

 

Combining lessons learned in Tutorial 10 with Tutorial 11 can be used to perform a risk-based helideck turbulence study.

 

This short guide will start at the end of Tutorial 10:

 

1. Open the Tutorial 10 file with the completed helideck simulation data

2. For any risk analysis with in:Flux a Risk Data Set needs to be defined:

3. From the Add Items tab, select Risk Data Set

4. Leave the Name as "Risk Data Set 01"

5. Set the Simulations to be All Ventilation Simulations

6. Once the above is done, the Vertical Fluctuating Velocities will appear as a Variable, select this term as the variable.

7. Use the option to define a region encompassing the rig and extending beyond it some, as in the figure below.

    

   

    

8. Ensure Run Now is selected

9. Click the Add Item button.

10. Once added to the project, in:Flux will extract the data for each of the 16 ventilation cases run.

11. Upon completion, open the Risk Manager to add probability data to each of the ventilation cases. Recall that this data can be entered before or after simulations have been solved.

12. Click the Wind Conditions Tab of the Risk Manager to view the wind probability data.

13. Now your screen will appear with four directions and four wind speeds as the figure below. This is because no probability information has been entered yet.

14. As 8 wind directions were simulated, click the "8" button at the top of the window, indicated by the red arrow below.

15. Enter a probability for each of the 8 wind directions.

     

    

     

16. Determine the number of wind speeds you want with your probability data, the default option is four, but more can be added. The figure above has used values of 5%, 15%, 35% and 45% to represent the 1 m/s, 5 m/s, 10 m/s, and 15 m/s speed ranges. Change these values to what is most applicable to your project

17. When all the data is entered click the Validate button to ensure all values add up to 100%. Depending on the data entered, the wind rose will change

     

    

     

18. Close the Risk Manager. Once data has been entered in the Risk Manager it is automatically applied to the cases in the project.

19. Now with a Risk Data Set defined and probability data entered a risk contour of exceedance can be created

    1. From the Add Items tab, choose Risk Contour

    2. Choose Risk Data Set 01 created above as the Risk Data

    3. Set the Data Type to Probability as only ventilation cases were run for this project.

    4. Enter the Exceedance to be 1.5 m/s as mentioned in CAP 437 as the lower bound (noting that 1.75 m/s is listed)

    5. Set the Offset at value to be "Z = 36 meters"

    6. Click Add Item

20. Right-click on the contour in the project items tab and choose the 'Link to Legend'. Depending on the values entered your screen may be similar to the figure below.

 

 

 

Alternatively, changing step 6.c. above, selecting the Data Type as Scenario will create a contour showing how many cases had above the exceedance value of 1.5m/s for the vertical fluctuating velocities. Red in the figure below represents 5 cases which exceed the entered amount.

 

 

 

The Color Map can be changed, and transparency added to the contour to better highlight regions of concern.