Extrusion operators are used to construct pointwise relations between source and destination points. Lets consider a laser heating example where you have a moving heat source, the laser, and a moving geometry. The parameters J_s, q, k, \textrm{and } T represent the following, respectively: the saturation current density, the electronic charge, Boltzmanns constant, and temperature. Good luck The upper layer soil, the lower layer soil, and the retaining wall. Email: support@comsol.com. The settings of the General Extrusion coupling operator are shown below: Alle Rechte vorbehalten. It can be used for a variety of different purposes, examples of which are presented here. Using source and destination maps to define implicit relations between source and destination coordinates in a General Extrusion operator. Settings used to revolve data about the azimuthal axis of a cylindrical coordinate system. General Extrusions, Inc. | Aluminum Extrusion for Ohio The General Extrusion operator maps expressions defined on a source to an expression that can be evaluated on any destination geometry where the destination map expressions are valid. As you can see, they are in the same location but are different boundaries. A one-to-one source map makes the search return, at most, one source point for a given destination point. I deplore the glaring oversight of COMSOL: Considering how frequently one encounters problems that include a combination of Rotationally-Symmetric and Cartesian components, that COMSOL has not seen fit to provide a specific operator for this case! From such source-destination pairs, one can infer the general mapping from superposition. Your internet explorer is in compatibility mode and may not be displaying the website correctly. A destination map and source map is specified here. Can you help me out? As the excavation reaches their depths, the struts are activated as long as the horizontal wall deflection is greater than what we allow it to be. COMSOL Multiphysics will take care of T_s^{-1}(T_d(x_d,y_d)), a necessary step in identifying the source coordinates. Left: Temperature varies linearly from left to right. The Periodic Flow condition is used to set the velocity so it is identical at the inlet and outlet boundaries, allowing us to specify a pressure drop over a single unit cell. Once a strut is activated, it will generate a force proportional to the struts stiffness and the horizontal displacement. The temperature will vary linearly with x. In these first two examples, the Use source map check box in the Source section of the settings window has been left unchecked. Considering a variable defined on the xy-plane within a unit square centered at the origin, as shown above, it is possible to implement a variety of transforms simply via different destination maps, and leaving the source map unchanged. Similar to the first two, for the third strut, add the third strut boundary and change stage 2 to stage 3. These indices are, in a sense, coordinates of an intermediate mesh, and a General Extrusion operator matches source and destination points that have the same intermediate coordinates. In this example, the operator is used by the Transport of Diluted Species interface to define the velocity field (illustrated below). In this example, since the x, y, and z-coordinates of the destination map are explicitly specified without any association with the coordinates of a geometric entity, it doesnt matter where we evaluate the General Extrusion coupling operator. The rest of the boundary loads will describe the three struts. Given an expression defined on a plane, e.g., the xy-plane, it is desired to map this data along the z direction. Sample data defined on the xy-plane, centered at the origin. COMSOL on Twitter: "Using the General Extrusion coupling operator in So lets revisit the Advanced settings and switch back Mesh search method to Use Tolerance the defaults is 0.3 which we have seen to fail in this case we have to search across a 0.1m gap, and we have meshed with 0.2m mesh-elements, thus we need, tol=search_distance/element_size=0.1[m]/0.2[m]=0.5. Thank you Walter for a wonderful discussion. Phone: (330) 783 0270 Fax: (330) 788 1250 Email: sales@genext.com P.O. Here, the p-n junction in a diode is represented by a thin gap in the geometry. Several cases are illustrated in the table below. Name: genext1 To explore the use of General Extrusion operators in other types of situations, consult the following blog posts: By providing your email address, you consent to receive emails from COMSOL AB and its affiliates about the COMSOL Blog, and agree that COMSOL may process your information according to its Privacy Policy. It also provides design assistance and engineering support. The Shockley diode equation for the current-voltage (I-V) relation is used at the junction. For circular periodicity, a rotation matrix, not a linear shift, must be used in the destination map. Lets now explore how to use a General Extrusion operator to copy data from a 2D axisymmetric component to a 3D component, such that the source and destination points correspond to the same point in space. We can tag the different sides as 1 and 2, as illustrated in the figure below. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version A little calculus gives us the arc length of the parabola between the origin and the source point (x,y). Example 1 In our earlier blog post on Linear Extrusion operators, we considered an affine mapping that pairs up points 1, 4, and 2 in the source domain to points 1, 5, and 3 in the destination domain. Part 2: Mapping Variables with General Extrusion Operators - COMSOL Unknown function or operator. Thanks for replying. Select the top strut and then total force as the load type. The source domain(s) can be the domain(s) on which the destination point(s) are defined. General Extrusions, Inc. continues its tradition as a leading manufacturer of aluminum extrusions where quality always comes first. In such cases, we can use projection, integration, average, maximum, or minimum component couplings. Clear the selection and add the middle strut, then change the expression from stage 1 to stage 2 to activate it only when the depth moves below the second strut. Temperature evaluated at a point on the geometry corresponding to the focal point of the moving laser. Forming an assembly creates an identity pair between the wall soil and wall diaphragm boundaries. Now that the velocity field is defined throughout the modeling domain, the species concentration at the inlet is defined via the Inflow boundary condition. \rho C_{p} \frac{\partial T}{\partial t} + \rho C_{p} \mathbf{u} \cdot \nabla T = \nabla \cdot (k \nabla T). Note: This discussion is about an older version of the COMSOLMultiphysics software. If the structural boundary conditions are not axisymmetric, we can save time by performing an axisymmetric thermal analysis in one component, and then mapping the temperature from the 2D axisymmetric domain to the 3D domain for structural analysis in another component. The parabola is the source. There are some models. When using Linear Extrusion operators, we visually indicate the mappings for enough points (bases) and COMSOL Multiphysics figures out how to transform the remaining points. Where might you use it in your multiphysics modeling? I guess your problem is that there is no recalculation after defining genext1, and this error will not be prompted after the calculation. To begin, lets focus on how to replicate a Linear Extrusion operator with a General Extrusion operator. If you have already computed the solution to the finite element problem, then you can simply evaluate temperature at the destination points by clicking on the update solution option in the Study toolbar, or you can dynamically probe the variable genext1(T) evaluated at a point while you compute the solution to the finite element problem. This can be either an explicit definition of the source point P_s as a function of P_d or an implicit relation between P_d and P_s. Create a second line graph, showing the surface settlement, or vertical displacement, as a function of the distance from the wall. For example, to map data from a boundary around a centerline, introduce a cylindrical system, and use those coordinate system variables to define the source and destination map. the setting of the extrusion is shown in the attachment (the .PNG file ). The information provided may be out of date. In 4.0a, I can define a general extrusion coupling, and the source domain is applies to. Settings used to revolve data about the azimuthal axis of a cylindrical coordinate system. To do so, you can use General Extrusion operators to map the fields from the stator to the slider. Thus, the second line y^iexpression is left blank. The plot below shows the graph for temperature evaluated at a point located 0.5 inches from the center of the rotating disk: Submit feedback about this page or contact support here. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Now, add a free triangular for the remaining geometry. One application of a General Extrusioncoupling is to mirror the solution on the x-axis. Sample data defined on the xy-plane, centered at the origin. Settings used to map data from a boundary parallel to the xy-plane along the z direction. unfortunately, I get the following error. This applies a varying species concentration over the inlet boundary. Today, we will discuss General Extrusion operators, which are designed to handle nonlinear mappings and the mapping of variables between geometric entities of different dimensions. It is also possible to define the mapping in terms of coordinate systems. The Micromixer tutorial, available in our Application Gallery, is an example of such a model. Ivar. Using General Extrusion Operators to Model Rotation | COMSOL Blog If excavating close to a retaining wall, youre subjecting it to additional forces it was not originally designed for, and it may require subsequent support. General Extrusions is owned and run by the Schuler family. The number of destination map expressions is the same as the space dimension of the intermediate mesh. L(x,y) = \int_{o}^{x}\sqrt{1+(y\prime)^2}d\tau = \frac{x}{2}\sqrt{1+4(\frac{x}{d})^2}+\frac{d}{4}\ln(2\frac{x}{d}+\sqrt{1+4(\frac{x}{d})^2}). Previously on the blog, we introduced you to Linear Extrusion operators and demonstrated their use in mapping variables between a source and a destination. The General Extrusion operator will map data from the boundary into the volume, along the z direction, as shown in the following screenshots. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Extrusion operators can be used to make couplings between points in the same component or different components. listed if standards is not an option). This can be useful for analysis; for example, to probe the solution at a point that is moving in time but is associated with a stationary geometry. Currently we are ISO 9001 certified. The variable Disp is individually defined within each of the three domains, as shown in the figure below. Struts are activated once the excavation reaches their depths by using a boolean expression. The company produces standard and custom aluminum extrusions for manufacturers in the appliance, medical equipment, transportation, and automotive markets, among others. To implement, define a General Extrusion operator on a boundary parallel to the xy-plane, with the z-expression blank for both the Source Map and a Destination Map. Several cases are illustrated in the table below. FIGURE 1. We can similarly evaluate the temperature at any other point. Each side of the junction becomes a source entity in one of the extrusion operators, as depicted below. When building the mapping, it is important to ask the following question: Given the coordinates of the destination point, how do we go to the source point? General Extrusions, Inc. can provide complete aluminum extrusion components including your finish requirements. Thank you for your time. I defined a general extrusion operator, then defined variables such as T_sf = genext1(comp1.T), Y_sf = genext1(Y) and so. I am trying to implement the Periodic Boundary condition in a 3D model by following your post but I have some questions. The General Extrusion operator maps expressions defined on a source to an expression that can be evaluated on any destination geometry where the destination map expressions are valid. A symmetry is used because the modeled excavation is only the right half of the full excavation. For example, to map data from a boundary around a centerline, introduce a cylindrical system, and use those coordinate system variables to define the source and destination map. Take a look at the figure below. If we know this ahead of time, it is possible to exploit the periodicity to reduce computational requirements. The first boundary load is added for the horizontal soil boundaries. Is it possible to do this within GUI, or do i have to do it via MATLAB? The last step before computing the model is defining a range of depth parameters for the parametric sweep. There are two ways to model an excavation in COMSOL Multiphysics, both of which include a parametric sweep. Settings used to revolve data about the azimuthal axis of a cylindrical coordinate system. listed if standards is not an option). so we choose 0.6 to be on the safe side. Here, V refers to the electric potential at a point on the bottom side, while genext1(V) refers to the electric potential vertically on the top side. Similarly, on side 2, we need access to the electric potential V_1 on the other side of the junction. The parts can exist in geometries of different space dimensions. Because the source and destination objects have different dimensions, affine transformations are impossible. However, if we want to use variables from a 2D axisymmetric component in the physics node of a 3D component (i.e., thermal expansion), we need to utilize General Extrusion operators. The Graphics Window: Effective and Beautiful Postprocessing, Generating Microsoft PowerPoint Slideshows from Your Models, Combining Adaptive Mesh Refinement with Data Filtering. Please feel free to contact us if you have any questions! Good luck Although it is not strictly necessary to do so, the mesh is copied from the one domain used to solve for the fluid flow to all of the other domains. This applies a varying species concentration over the inlet boundary. Thank you. -- Too simple. An example of defining such a rotation matrix is detailed in this previous blog post. When this check box is left unchecked, COMSOL Multiphysics assumes that we have explicit expressions for each coordinate of the source as functions of coordinates of the destination. Welcome to General Extrusions Inc. In addition to simply copying known quantities, these operators can be used to create nonlocal couplings between unknown variables, as illustrated in our p-n junction example. The General Extrusion operator is used to define the velocity field in all three periodic domains. Settings used to map data from a boundary parallel to the xy-plane along the z direction. In this example, one expression is sufficient enough to uniquely relate any destination point in the square domain to a source point on the parabolic curve. All points in the domain with the same distance from the origin copy temperature from the same point on the parabola. The company's manufacturing operations, which include a Youngstown, Ohio plant, comprise 220,000 square feet. This time in the x direction and using the second general extrusion operator in the u0 field. Alternatively, from the Extrude from list, select Work plane to extrude objects from a work plane. General Extrusions specializes in providing secondary fabrication operations to transition an aluminum extrusion to a finished component. Within the original domain, a displacement of zero is used. For such a unit cell model, the walls of the channels are set to the Wall, No Slip condition. -- The corresponding normal current density for the Normal Current Density 2 node applied to edge 3 is -Js*(exp((V-genext1(V))/kTbyq)-1). Extrusion operators can be used to access the electric potential on the other side of a junction. A typical microfluidic device. General Extrusions is engaged in fabrication, anodizing, and powder coating, as well as aluminum finishing and machining. We want a depth ranging from 0 to -26 meters with a step size of two meters.
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