Add process output line limit, skip duplicate problem types in task flow, split fluid theory manuals and consolidate 1.3.0 release notes

Author: tomas-soltys

src/fea/CMakeLists.txt

@@ -464,6 +464,8 @@ fea_add_icon_resources(icons-action "/icons/action"
         pixmaps/range-close.svg
         pixmaps/range-ok.svg
         pixmaps/range-remove.svg
+        pixmaps/range-spin_down.svg
+        pixmaps/range-spin_up.svg
         pixmaps/range-undo.svg
 )
 

src/fea/doc/RELEASE_NOTES.md

@@ -5,6 +5,10 @@
             "title": "Acoustics",
             "file":  "theory_acoustic.md"
         },
+        {
+            "title": "Contaminant dispersion",
+            "file":  "theory_fluid_particle.md"
+        },
         {
             "title": "Electro-statics",
             "file":  "theory_electrostatics.md"
@@ -17,6 +21,10 @@
             "title": "Heat transfer",
             "file":  "theory_heat.md"
         },
+        {
+            "title": "Heat transfer in fluids",
+            "file":  "theory_fluid_heat.md"
+        },
         {
             "title": "Magneto-statics",
             "file":  "theory_magnetostatics.md"

src/fea/help/theory/en/index.json

@@ -0,0 +1,218 @@
+# Heat Transfer in Fluids - Theory Manual and User Guide
+
+This document describes the fluid heat solver of Range FEA - `RSolverFluidHeat`,
+which serves the **Heat transfer in fluids** problem type: the equation it
+solves, the meaning of every input it accepts, its coupling to the heat solver
+of a solid, and the parts of the graphical user interface that drive it.
+
+Heat transfer in fluids is solved on the flow field of an **Incompressible
+viscous flow** task. The flow solver, its boundary conditions, its non-linear
+iteration and its time march are described in the [Fluid flow](theory_fluid.md)
+manual, and the heat solver of solids in the [Heat transfer](theory_heat.md)
+manual.
+
+**Contents**
+
+1. [Theoretical background](#1-theoretical-background)
+2. [Graphical user interface](#2-graphical-user-interface)
+3. [Limitations](#3-limitations)
+
+---
+
+## 1. Theoretical background
+
+### 1.1 Primary unknown - the temperature
+
+The primary unknown is the **temperature** `T` in `K`, one degree of freedom per
+node.
+
+| Problem type | Solver | Primary unknown | Units | DOF per node |
+|---|---|---|---|---|
+| Heat transfer in fluids | `RSolverFluidHeat` | temperature | `K` | 1 |
+
+The problem type **requires** an *Incompressible viscous flow* task in the same
+problem: it reads the velocity field from its result and never computes it
+itself.
+
+### 1.2 Governing equation
+
+**Heat transfer in fluids** solves the advection-diffusion of temperature on the
+flow field,
+
+```
+rho * c * ( dT/dt + v . grad(T) ) = div( k * grad(T) ) + q
+```
+
+with the same SUPG stabilisation of the convective term as the flow solver and
+the same theta time march. The velocity `v` is **recovered from the flow
+result**, not solved here - which is why the problem type requires an
+*Incompressible viscous flow* task.
+
+| Symbol | Meaning | Units | Source |
+|---|---|---|---|
+| `T` | temperature | `K` | solved for |
+| `v` | velocity | `m/s` | the flow result |
+| `k` | thermal conductivity | `W/(m*K)` | material property |
+| `c` | heat capacity | `J/(kg*K)` | material property |
+| `rho` | density | `kg/m^3` | material property |
+| `q` | heat source density | `W/m^3` | Heat condition, Joule heat, radiation |
+
+The difference from the plain **Heat transfer** problem type is exactly the
+`v . grad(T)` term: energy is carried along by the moving fluid rather than only
+conducted. That also means this solver has no convection boundary conditions -
+there is nothing to correlate, since the heat leaving a wall into the fluid is
+resolved by the mesh rather than modelled.
+
+### 1.3 Boundary conditions
+
+| Boundary condition | Type | Applies to | Components |
+|---|---|---|---|
+| Temperature | explicit (Dirichlet) | point, line, surface, volume | Temperature `[K]` |
+| Heat | natural, source | point, line, surface, volume | Heat `[W]` |
+
+**Temperature** holds the nodes of its entity at the given value. Assign it to
+the inlet surface to set the temperature of the fluid entering the domain, and
+to a wall to model a heated or cooled boundary.
+
+**Heat** is a source and takes the **total power in `W`** delivered into the
+entity, spread over the measure of the entity before assembly - the same
+convention as the heat solver. *Heat rate (unit area)* and *Heat rate (unit
+volume)* are offered by the interface for this problem type but are **not read**
+by the fluid heat solver; use *Heat* for a source here.
+
+Every component is a **table against time**.
+
+The flow conditions - walls, inlets and outlets - belong to the flow task and
+are described in the [Fluid flow](theory_fluid.md) manual.
+
+### 1.4 Conjugate heat transfer
+
+A wall between a meshed fluid and a meshed solid carrying the **Forced
+convection** condition of the plain *Heat transfer* solver couples the two. Once
+the heat solver has run, the fluid heat solver holds the wall nodes at the
+temperature of the solid - until then the wall is insulated - and hands back,
+for every wall element, the pair `(h, Tf)` that reproduces the heat flux its
+solution takes through the wall. The heat solver applies that pair as a
+convection condition. The flux is the residual of the fluid equations at the wall
+nodes, consistent with the discretisation, so it stays accurate in a thin thermal
+boundary layer. The wall temperature is relaxed with an Aitken factor from pass
+to pass, which settles the exchange in a handful of passes. The
+[Heat transfer](theory_heat.md) manual describes the scheme under *Conjugate
+heat transfer*. Radiative heat and Joule heat arriving from other solvers are
+added to the source term the same way as in the heat solver.
+
+### 1.5 Convergence
+
+Uncoupled, the fluid heat solver reports itself as converged unconditionally -
+it is linear once the flow field is fixed, so one solve is the final answer. A
+group holding both the flow and the fluid heat task therefore ends when the flow
+task converges. With coupled walls it reports the relative change of its
+temperature field instead, so the group iterates until the wall temperature has
+settled.
+
+### 1.6 Initial conditions
+
+| Initial condition | Effect |
+|---|---|
+| Temperature | initial temperature field |
+
+Initial conditions are read on the **first run only**; after that the field
+marches from the previous result. A boundary condition overrides an initial
+condition where the two meet.
+
+### 1.7 Results
+
+| Result | Apply to | Meaning |
+|---|---|---|
+| Temperature `[K]` | node | the solved temperature field |
+| Heat flux `[W/m^2]` | element | conductive flux `-k*grad(T)` |
+
+---
+
+## 2. Graphical user interface
+
+Everything relevant lives in the **Solver** dock (`Problem`,
+`Boundary conditions`, `Initial conditions`, `Material`, `Results` tabs), the
+**Problem** menu and the **Model** dock.
+
+### 2.1 Selecting the problem
+
+`Problem` -> `Problem(s) task flow` (`Ctrl+P`) opens the problem task flow
+dialog. The combinations worth knowing:
+
+- *Incompressible viscous flow* and *Heat transfer in fluids* in one group - a
+  heated or cooled flow;
+- *Heat transfer in fluids* and a separate *Heat transfer* task on a meshed
+  solid, the fluid heat task first, in one group of several iterations -
+  conjugate heat transfer through the walls carrying *Forced convection*.
+
+The problem type requires a flow task to be present. The task group values -
+**# of iterations** and **Convergence** - are described in the
+[Fluid flow](theory_fluid.md) manual.
+
+### 2.2 Problem tab
+
+**Time-solver** - shown since the problem type is time-dependent. Leave it
+disabled for a steady-state run. Its fields are described in the
+[Fluid flow](theory_fluid.md) manual.
+
+The problem type has no setup group box of its own. Everything else is assigned
+per entity in the condition tabs.
+
+### 2.3 Material tab
+
+| Property | Units | Comment |
+|---|---|---|
+| Density | `kg/m^3` | `rho`, about `1000` for water, `1.2` for air |
+| Dynamic viscosity | `kg/(m*s)` | `mu`, about `1.0e-3` for water, `1.8e-5` for air |
+| Thermal conductivity | `W/(m*K)` | `k`, about `0.6` for water, `0.025` for air |
+| Heat capacity | `J/(kg*K)` | `c`, about `4180` for water, `1005` for air |
+
+An entity missing any required property is not solved, and the setup checker
+warns before the run starts. The shipped material database includes **Water**
+and **Air**, which is usually the whole of this step. Every property is a table
+against temperature, evaluated at the element temperature of the previous run.
+
+### 2.4 Boundary conditions tab
+
+**Temperature** and **Heat** appear once a *Heat transfer in fluids* task is in
+the task flow - see section 1.3. Every component is a table against time; click
+**Edit time dependent values** to enter values against time.
+
+### 2.5 Initial conditions
+
+The `Initial conditions` tab offers *Temperature*. It sets the starting field of
+the first run.
+
+### 2.6 Matrix solver setup
+
+`Problem` -> `Setup Problem(s) matrix solver` configures the iterative solvers.
+The fluid heat solver uses the **GMRES** entry, since its matrix is not
+symmetric.
+
+### 2.7 Monitoring points and results
+
+`Problem` -> `Define monitoring points` can record *Temperature*. The `Results`
+tab shows temperature as a node scalar and heat flux as an element vector.
+
+---
+
+## 3. Limitations
+
+- **No buoyancy.** The density does not depend on temperature, so a *Heat
+  transfer in fluids* result never drives the flow it was computed on. Natural
+  convection, thermal plumes and stratification cannot be modelled.
+- **The coupling to the flow is one-way.** The flow drives the heat transport;
+  the temperature never changes the flow.
+- **`Heat rate` conditions are ignored.** *Heat rate (unit area)* and *Heat rate
+  (unit volume)* are offered by the interface for *Heat transfer in fluids* but
+  are not read by `RSolverFluidHeat`; only the *Heat* condition reaches it. The
+  plain *Heat transfer* problem type does read all three.
+- **No convection boundary conditions.** Heat leaving a wall into a meshed fluid
+  is resolved rather than correlated, so the *Simple*, *Forced* and *Natural
+  convection* conditions belong to the plain heat solver. Conjugate heat
+  transfer is set up as a *Heat transfer* task on the solid whose *Forced
+  convection* walls read the computed fluid state.
+- **No turbulence model.** The flow is laminar, see the
+  [Fluid flow](theory_fluid.md) manual, so turbulent heat transfer is not
+  represented.