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June 22, 2006, 21:12 |
Relief Plots in CFX
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#1 |
Guest
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I used relief plots in TASCflow for visualizing draft tubes. Unfortunately I have not found this capability in CFX, any suggestions?
thanks |
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June 23, 2006, 05:56 |
Re: Relief Plots in CFX
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#2 |
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maybe User Surface, Offset From Surface by Variable can be used for relief plots?
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June 23, 2006, 06:38 |
Re: Relief Plots in CFX
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#3 |
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that produced the effect, but it is not nearly as flexible to produce a visually appealing plot.
thanks for the suggestion. |
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June 23, 2006, 06:42 |
Re: Relief Plots in CFX
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#4 |
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Just out of curiosity , what kind of plot do you want to create? Mail me.
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June 23, 2006, 10:16 |
Re: Relief Plots in CFX
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#5 |
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Below is what I would like to do. Really easy in TASCflow, and as you can see it helps to visualize the velocity topology better than contours and vectors.
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June 26, 2006, 08:23 |
Re: Relief Plots in CFX
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#6 |
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I think that an offset user surface does not completely do what you want. As far as I can be see (but I could be wrong) CFX-Post creates a surface based on the offset (say speed), but if you want to colour it, it will do so based on the speed at the offset surface and not on the original location.
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June 27, 2006, 01:22 |
Re: Relief Plots in CFX
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#7 |
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Maybe you can plot it by height (or offset) and scale the variable to fit to pressure, velocity or any other variable.
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June 28, 2006, 02:35 |
Re: Relief Plots in CFX
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#8 |
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Somewhat like this:
Pressure distribution around a cylinder - Relief plot of a transient calculation. |
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June 28, 2006, 09:53 |
Re: Relief Plots in CFX
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#9 |
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that look really good, but it seems you are offsetting a contour? could you please provide some additional details on how you did that. i would appreciate it.
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June 28, 2006, 13:05 |
Re: Relief Plots in CFX
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#10 |
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ok, learned a few things. Numerous ways to skin this cat.
Method: Offset from Surface Type: Normal Mode: Uniform Distance: 0.05 * Velocity or Type can be Variable and in the field you can enter 0.05*Velocity. Now what I have not been able to do is make that NICE contour image you posted. any details on that would be appreciated. |
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June 29, 2006, 04:12 |
Re: Relief Plots in CFX
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#11 |
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Here's how i did the relief surface based on pressure:
I have created a "Quantative" variable called Offset which is defined as: Offset = Pressure / 400 [Pa/m] My original XY-Plane (at Z=0.005m) is then used as an offset from Surface: User Surface / Offset from Surface / Plane 1 / Normal / Variable / Offset to give the relief surface. I've then created a new variable PressureZ to give the correct color of the pressure on the curvatured surface. Otherwise it will give you the pressure at the specified offset location: PressureZ=Z*400[Pa/m]-2[Pa] The "-2[Pa] comes from the original "Plane 1 * 400". Then it is easy to create a contour on the User Surface 1 with the variable PressureZ to give the correct colors and legend including correct Units! I've also changed the colour map to "Rainbow 6" just to give it another look... The value 400[Pa/m] is chosen arbitrary to give a smooth surface with sufficient amplitude. Hope that helps. |
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June 29, 2006, 11:15 |
Re: Relief Plots in CFX
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#12 |
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Interesting idea, but it will only work if you are coloring by the same variable as the offset, will only work for a plane and will not work if the user surface is outside of the domain.
This would be a nice thing to add to Post, however. -Robin |
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June 29, 2006, 11:30 |
Re: Relief Plots in CFX
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#13 |
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A sure way to do this, albeit complicated, is to do the following:
1. Export the data on the original surface (export1.csv) 2. Create the offset surface. 3. Export the geometry (including node connectivity) on the offset surface (export2.csv) 4. Open both exported files in a spreadsheet. Copy the column(s) of variables from the original (export1.csv) to the displaced surface (export2.csv). Save it back to a .csv file and be careful that Excel does not truncate your values. It will by default. To avoid this, select all of the cells and change the number format to General. 5. Create a User Surface using the "From File" method and load export2.csv. The variables loaded on the user surface will appear as <Variable Name> on <User Surface Name>. Voila! Maybe I'll write a macro to do it when I have some time. Regards, Robin |
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June 30, 2006, 02:08 |
Re: Relief Plots in CFX
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#14 |
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It works fine even if the user surface is outside the doamin. And since the coloring variable is proportional to the offset, it works fine. Have a look at the following two plots. The original and the relief plot.
Note that the user surface is outside of the wireframe and also that the units correspond. |
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June 30, 2006, 03:47 |
Re: Relief Plots in CFX
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#15 |
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Here's a session file (*.cse) creating what I've done.
Change the varibles zxyplane and curvatureparameter # SESSION FILE. RELIEF START. MAKE PRESSURE RELIEF.CSE LIBRARY: CEL: EXPRESSIONS: zxyplane=0.005 [m] END END END EXPRESSION EVALUATOR: Evaluated Expression = zxyplane END > forceupdate EXPRESSION EVALUATOR PLANE:Plane 1 Apply Instancing Transform = On Apply Texture = Off Blend Texture = On Bound Radius = 0.5 [m] Colour = 0.75, 0.75, 0.75 Colour Map = Rainbow Colour Mode = Constant Colour Scale = Linear Colour Variable = Pressure Colour Variable Boundary Values = Hybrid Culling Mode = No Culling Direction 1 Bound = 1 [m] Direction 1 Orientation = 0 [degree] Direction 1 Points = 10 Direction 2 Bound = 1 [m] Direction 2 Points = 10 Domain List = All Domains Draw Faces = On Draw Lines = Off Instancing Transform = Default Transform Invert Plane Bound = Off Lighting = On Line Colour = 0, 0, 0 Line Colour Mode = Default Line Width = 1 Max = 0.0 [Pa] Min = 0.0 [Pa] Normal = 1 , 0 , 0 Option = XY Plane Plane Bound = None Plane Type = Slice Point = 0 [m], 0 [m], 0 [m] Point 1 = 0 [m], 0 [m], 0 [m] Point 2 = 1 [m], 0 [m], 0 [m] Point 3 = 0 [m], 1 [m], 0 [m] Range = Global Render Edge Angle = 0 [degree] Specular Lighting = On Surface Drawing = Smooth Shading Texture Angle = 0 Texture Direction = 0 , 1 , 0 Texture File = Texture Material = Metal Texture Position = 0 , 0 Texture Scale = 1 Texture Type = Predefined Tile Texture = Off Transform Texture = Off Transparency = 0.0 Visibility = On X = 0.0 [m] Y = 0.0 [m] Z = zxyplane OBJECT VIEW TRANSFORM: Apply Reflection = Off Apply Rotation = Off Apply Scale = Off Apply Translation = Off Principal Axis = Z Reflection Plane Option = XY Plane Rotation Angle = 0.0 [degree] Rotation Axis From = 0 [m], 0 [m], 0 [m] Rotation Axis To = 0 [m], 0 [m], 0 [m] Rotation Axis Type = Principal Axis Scale Vector = 1 , 1 , 1 Translation Vector = 0 [m], 0 [m], 0 [m] X = 0.0 [m] Y = 0.0 [m] Z = 0.0 [m] END END LIBRARY: CEL: EXPRESSIONS: curvatureparameter=90000 [m^-1] END END END EXPRESSION EVALUATOR: Evaluated Expression = curvatureparameter END > forceupdate EXPRESSION EVALUATOR LIBRARY: CEL: EXPRESSIONS: Offset=Pressure / (curvatureparameter * 1[Pa]) END END END EXPRESSION EVALUATOR: Evaluated Expression = Offset END > forceupdate EXPRESSION EVALUATOR USER SCALAR VARIABLE:Relief offset Boundary Values = Conservative Calculate Global Range = Off Expression = Offset Recipe = Expression Variable to Copy = Pressure END USER SURFACE:User Surface 1 Apply Instancing Transform = On Apply Rotation = On Apply Scale = On Apply Texture = Off Apply Translation = Off Associated Boundary = Domain Interface 1 Side 1 Associated Boundary Specified = On Blend Texture = On Colour = 0, 0.8, 0 Colour Map = Rainbow Colour Mode = Constant Colour Scale = Linear Colour Variable = Pressure Colour Variable Boundary Values = Hybrid Contour Level = 1 Culling Mode = No Culling Domain List = All Domains Draw Faces = On Draw Lines = Off File Units = m Input File = data.txt Instancing Transform = Default Transform Lighting = On Line Colour = 0, 0, 0 Line Colour Mode = Default Line Width = 1 Maintain Conservative Values = On Max = 0.0 [Pa] Min = 0.0 [Pa] Offset Direction = 1 , 0 , 0 Offset Distance = 0.0 [m] Offset Mode = Variable Offset Type = Normal Offset Variable = Relief offset Option = Offset From Surface Principal Axis = Z Range = Global Render Edge Angle = 0 [degree] Rotation Angle = 0 [degree] Rotation Axis From = 0 [m], 0 [m], 0 [m] Rotation Axis To = 1 [m], 0 [m], 0 [m] Rotation Axis Type = Principal Axis Scale Factor = 1.0 Specular Lighting = On Surface Drawing = Smooth Shading Surface Name = Plane 1 Texture Angle = 0 Texture Direction = 0 , 1 , 0 Texture File = Texture Material = Metal Texture Position = 0 , 0 Texture Scale = 1 Texture Type = Predefined Tile Texture = Off Transform Texture = Off Translation Vector = 0 [m], 0 [m], 0 [m] Transparency = 0.0 Use Absolute Pressure = Off Visibility = On OBJECT VIEW TRANSFORM: Apply Reflection = Off Apply Rotation = On Apply Scale = On Apply Translation = Off Principal Axis = Z Reflection Plane Option = XY Plane Rotation Angle = 0 [degree] Rotation Axis From = 0 [m], 0 [m], 0 [m] Rotation Axis To = 1 [m], 0 [m], 0 [m] Rotation Axis Type = Principal Axis Scale Vector = 1 , 1 , 1 Translation Vector = 0 [m], 0 [m], 0 [m] X = 0.0 [m] Y = 0.0 [m] Z = 0.0 [m] END END PLANE:Plane 1 Visibility = Off END LIBRARY: CEL: EXPRESSIONS: Pressure Relief=(Z-zxyplane)*curvatureparameter*1[Pa] END END END EXPRESSION EVALUATOR: Evaluated Expression = Pressure Relief END > forceupdate EXPRESSION EVALUATOR USER SCALAR VARIABLE:PressureZ Boundary Values = Conservative Calculate Global Range = Off Expression = Pressure Relief Recipe = Expression Variable to Copy = Pressure END USER SURFACE:User Surface 1 Visibility = Off END CONTOUR:Contour 1 Colour Variable = PressureZ Colour Variable Boundary Values = Conservative Contour Range = Local Location List = User Surface 1 Number of Contours = 11 END |
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June 30, 2006, 08:01 |
Re: Relief Plots in CFX
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#16 |
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OK. I see what you've done. You have related the location to the offset. The only problem is that this would only work for regular geometric shapes. It would be hard to do on an arbitrary geometry because you would not know what the offset was.
Still very clever. A simple improvement would be to replace your curvature parameter with a simple normalization of the offset variable, multiplied by a maximum offset distance. If you want the max offset to be 1 [cm], then do the following (using Pressure and Plane 1 as an example): Pressure/maxVal(Pressure)@Plane 1 * maxDisp maxDisp = 1 [cm] Regards, Robin |
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